What the DMG doesn't tell you(or I missed); one of my players is troubled by my DMing

[MonkeySage]

To explain a bit, my group recently finished their first dungeon, one I designed for a level 1 party of newbies. Now, this was the first dungeon I designed, so I didn't expect to create Michelangelo's David, but honestly I think it may have been too easy, even for a group of level 1s.
The dungeon was an abandoned mineshaft, so I wasn't sure how to have enemies patrolling, nor was I clear on how to give the group freedom to wander(I designed the mineshaft based on how I felt a real mineshaft would be laid out, and infact did research on that.)

Pretty much all the enemies went down in 2 or fewer hits: I gave them encounters based on challenge rating, hoping this would actually "Challenge" them, and it apparently did not. The boss fight itself consisted of a 3rd level goblin cleric, 2nd level hobgoblin monk, and 2 warriors. I underestimated my players apparently. Part of my difficulty is that one of the players is a drow ranger(LA +2). I probably should not have allowed him to play a drow in the first place but I'm not about to punish him for a mistake that I made.

The player also informed me that he felt an earlier random encounter with half a dozen coyotes was a lot more fun, by reason that they were out in the open.

Finally, there's the issue of plot vs freedom apparently. I try to keep railroading to a minimum, that little bit necessary to keep the story moving. But the above mentioned player is apparently used to sandbox games, and cares less about story than he does about doing whatever he wants, whenever he wants. I do not want to scare him off of D&D, but at the same time I'm needing advice for how I might accommodate him. Obviously, being in possession of an ordinary brain, and not an xbox for a brain there are things I cannot do. But part of his complaint was "I wanted to go the other way", and the decision to go a certain way was for the party to decide. They voted against him, and he still decided to follow them. He's blaming me for this.

There were a few other problems, but these are the major ones. I'm wondering if there is any advice that more experienced dungeon masters can offer(I should mention that this the first game i've run successfully; journey to the west is in the process of beign rebooted due to failure)

[IamL]

Yeah, CR is broken. It's bork.
Something I usually do when planning encounters (in order of importance, most to least, IMHO.)
Ultimate Question (all of the below) combine: Will this be fun to play?
1. Does this advance the story/plot/puzzle/adventure significantly?
2. Will it be an appropriate challenge? The best challenges require that adventurers use up many resources, but still win. You can fiddle with this, turning the dial up on boss fights and down on easy skirmishes. I often run through what my players' tactics might be and run encounters in my head.
3. Does it make logical, physical sense?
4. Does this encounter follow D&D/PF/other game RAW or RAI?

EDIt: got edit ninja'd by OP.

Yeah, that person will need to adjust. If he wanted to go another way, the party put it down to a vote, and he stayed with the party, it isn't your fault.
However, sandbox-type players typically like political intrigue/puzzle sort of adventures instead of dungeon crawls, so I might consider looking at if that's the right adventure style for you and your players.

[Phelix-Mu]

Alright, IamL touched on some big points, but I will say my part:

1.) CR is silly. It can be useful as a very vague guideline, but never rely on it. In the end, you usually get a feel for what will be challenging, but not overwhelming, simply by throwing a large variety of stuff at various parties across numerous campaigns.

2.) There are many good things to be said about using elements of pre-generated, playtested materials from published modules. As a maven of self-generated material myself, I also don't like to borrow, but starting out, it can be invaluable to see how established encounters run against a given party. Plus, it plain, flat out reduces prep-time for sessions, which leaves time for more important matters, like making the story compelling, engaging all of the characters, layering, and so forth.

3.) Sandbox v Railroad: there is surely a fine balance to be struck in this area. A character can run off and do his/her own thing alone as the player wishes, but don't be afraid to teach said character that the reason most adventurers travel in groups is because it is much safer to have a party at your back. I'm not suggesting you persecute the player for having an independent-minded character, but neither should you pull punches just because a pushover encounter for a whole party could easily spell the end of a solo character. Also, doing stuff in a group makes session run more smoothly and quickly, and avoids certain party dynamics that might not always be pleasant (but which might be seen as entertaining around other tables...it takes all sorts and whatnot).

4.) Encounter size: If the encounter is supposed to be challenging, it is almost always advisable to have there start out more enemies than there are party members. If all the party members can focus on 2-3 enemies, then enemies with superior CR will still get mowed down pretty quickly.

5.) D&D in it's current incarnation actually tends to have fairly short combats. Things that drag on for more than 3-4 rounds are pretty unusual, in my experience, though a time factor can intentionally be built in by the DM. So, if the enemies die fast, that is somewhat okay, because that is largely how the game shakes out. Not entirely unrealistic; if a group that specializes in killing things gets together and makes an effort, the things should probably die in fairly short order (as each combat round, six seconds, is actually quite long when in the throes of adrenaline and such).

[MonkeySage]

The next game will pretty much be pure role playing, though there will be one fight. Kind of an experiment for me, especially with 2 new players(post dungeon). The current party is:
Dwarven druid, level 2 (to be introduced during the fight)(has played 4e)
Gray elf wizard, level 2 (was one of the slaves they freed from the goblins)
Elf rogue, level 2 (has played d&d a long time ago)
Drow ranger, level 1 (has played Neverwinter, the MMO)
Half elf bard, level 2 (has run 4e)
Half elf ranger, level 2 (has never played before)
Human cleric of kord, level 2 (has played 4e)

So, what I had in mind was a group of medium-sized monstrous scorpions. At the moment I've settled for about 6 of them, some in hiding behind the sparse boulders and vegetation. Any advice for how I might tweek this encounter to make it more interesting?

[Lonely Tylenol]

What is the context of this encounter?

[MonkeySage]

Happenstance: The scorpions had been competing over an adult hare, just happened to be a small distance scattered over the road. I have not yet figured out where the druid comes into play.

[IamL]

Give the scorpions improved poison. Say, Con and Int damage. (Yes, Phelix-Mu, I recently used the trick on you.) But after they (probably) survive, they realize that the poison must have been manufactured...and so starts the hunt to find the person responsible.

[Phelix-Mu]

You have a large to very large party size. Action economy dominates the game at all levels; with such a large party, you really must have more of the enemy monsters, as anything big enough to survive multiple rounds will likely also one-shot characters that get solidly hit.

Usually, the party will have the upper hand in power, but pepper in the mooks to make fights last a bit longer and suck up more party resources. Well-played mooks can be quite dangerous in the wrong (read:RIGHT) hands, and goblins with tower shields, longspears, pit traps, and bows are a time-proven strategy for making life hard for low-level characters.

Overall, at low levels, I like to have adverse conditions play a role. Nighttime ambushes, rain, poor lighting, exhaustion and the like can lead to really memorable encounters.

For instance, try out the desert scorpions thing at night. The party night watch has heard a sound (and hopefully woken someone else up). They go to investigate, and find that the scorpions are clashing over which one gets to eat some dead carrion. The party can see the ones on the ground with darkvision or light sources, but they may easily miss another two scorpions that are chilling out behind a rock. Finally, if combat happens, have there be a chance that something big and nasty hears the sounds and comes to research the possibility of food. Give it decent stealth, and an intelligence to wait for the pcs to be off their guard or separated from one another.

[nedz]

Level 1 parties are very swingy. You could run the same encounter twice: one time it would be easy the next time the party would lose. This is mainly because they haven't worked out what they are doing yet, so they lack coherence; this is less of an issue with larger groups and 7 PCs is on the large size.

It also takes a few encounters for a DM to gauge the strength of the party but bare in mind that their power will increase, in relative terms, very rapidly at first.

[jokeaccount]

So...much...elf...Well these guys are definitely not optimizers but as others have said, CR is bad. The thing is that for each level up the guidelines with CR are that you will have to play around 9 battles or something. With so many fights ofc they will be lower CR. If you want to have fewer pointless battles and 1-2 serious ones then you gotta up the CR/don't use it at all. Let me give you an example battle of our campaign:

We were all party level 9 and one lvl 8: Ftr, Rog, Wiz, Cler, Bard (we are good-neutral so we didn't get a ranger). The encounter was 1 Frost Giant Cleric and 4 Frost Giant Barbarians. Ofc they had a special ability where everyone shared damage taken except the cleric whose damage was shared but he didn't receive any from the others. So they essentially had Damage taken/5. Plus I remember the cleric had something like 35 AC and a Staff with Cone of Cold, Wall of Ice and something else too. We were laughing at how retarded the battle was and almost started to bet on who would die last or something. However since the Wizard is correctly a Tier 1 class he trivialized the battle by succeeding a Spin Fated Baleful Polymorph on the Cleric and I think a fear on 2 of the barbarians or something. We easily picked them off afterwards etc. However if he wasn't super lucky and the giant succeeded his save we would have a super tough time.

[Fitz10019]

The carrion could be a person, a messenger/courier, who is carrying a leaky clay pot full of smelly goo. The smell drew the scorpions. Whoever sent this person out with this package planned on him never returning. The druid was trailing the smell, which agitated his animal companion. The courier is a goner. Who hired him? Why did that person want him dead? Who could get, or make, such a scorpion-luring goo?

Keep in mind that scorpions climb about as well as spiders, so they can use trees in ways the party can't.

[Chronos]

It's nearly impossible to make a good adventure for level 1 characters. Consider that encounter with the hobgoblins: No matter how easily they die, one of those hobs could easily have won initiative, and so gotten a hit in before dying. That hit could easily have been a critical hit. And a critical hit is fairly likely to kill a first-level character in one shot. Is an encounter where one of the party members dies in one shot an easy encounter? It's hard to argue so... but that's the exact same encounter where, in your game, the party won without breaking a sweat. And that's true of almost all combat encounters, at first level.

Basically, first level characters suck, and that's a feature, not a bug. First-level parties should spend most of their time doing everything they can to avoid combat, and only stand and fight when absolutely unavoidable, and even then with as many advantages as they can muster up (favorable terrain, surprise, etc.). This makes it that much more fun when they get a few levels on them, and realize that they don't have to run from everything any more.

[Yawgmoth]

Gonna be echoing a lot here but it's all stuff that needs to be said a hundred times:

1. CR is useless, ignore it. Too many moving parts in D&D for it to function, and your party is nearly double the expected party size so it'll double not function for you.

2. Levels 1-3 are incredibly swingy. One good hit from anything will paste a character, and if they get crit it's an almost guaranteed one hit death.

3. You can generally assume a combat will last (# of monsters)/(# of PCs) rounds, assuming completely average numbers. This is because damage is really simple to get if you go for any level of optimization, and casters will usually end one target per round (at least) because magic.

4. Your complaining player needs to understand the basic concepts of cooperation. If you're going out to eat with friends and they all vote pizza, and he says "but I wanted chinese!" what happens? The same is true of D&D.