Mini Campaigns for Training

[CityOfStreams]

So I'm a newer player but I picked it up pretty quickly. My DM who has been playing and DMing for at least 8 years now has told me I should consider DMing. I had tried to do a campaign this passed year, but we got busy with school and I also realized after the first encounter that I had not planned out nearly enough details for the story to be convincing. So now that school is over for the summer, and my main D&D buds are now scattered over the country there's no opportunity to continue my campaign. Well my DM came up with a rather good idea for me to improve my skills and versatility, as well as have a lot of fun.

He and I will be trading off this summer doing single session mini campaigns for each other over Skype. We'll be told the generally atmosphere of the campaign and backstory, but then we'll quickly roll up a new character and play. This is really going to help me with my encounter planning. I'm a fairly creative guy and coming up with plot twists, story arcs, and setting up an intricate and interesting world come relatively naturally to me, but the mechanical side of actually playing the DM staying neutral as an NPC, giving appropriate amounts and levels of monsters or loot, and all the other little things that go into DMing are new to me. So I'm really hopeful for these little campaigns to get me used to not getting hung up on any one part of my story or campaign in general.

So as far as actually coming up with creative campaign ideas I'm not too worried and I also think that's one department I should do myself. What I want from you guys is advice on things to keep in mind for these mini-missions, and any weird obscure tips you may have for me. Thanks!

[DrKerosene]

I think this uses PF tables, but it explains CR stuff and should be consistent if you use it for encounter building. https://docs.google.com/document/d/1nx-o8VAjhUwh3nnfzDQT-JA5eFLnN_BZJiBitGjBMDg/mobilebasic?pli=1

There are stories of solo-campaigns with one PC, or a Commoner PC, but it's basically a lot more streamlined gameplay. You have to ignore challenges the PC cannot deal with, and the link above covers most of what I wish I had known sooner.

Hirelings, Cohorts, Gestalt, can all fill-in holes, but they all have various levels of extra book-keeping.

Here are some relatively strong, at their level, builds you can use for one-off assistance DMPCs when the player wants something extra to fight along their side. http://www.minmaxboards.com/index.php?topic=2813.0
I like the third level sorcerer who heals.

[Uncle Pine]

So, tl;dr "do you have any tips about balancing encounters and creating creatures and loot"?

1. Read your PHB, MM and DMG. All of them, twice. If you have the time, read all the other books you have as well (starting from monster manuals and other books with lots of creatures, since you're interested in them). This will give you a good base of system mastery and knowledge of possible monsters' tactics and options you'll have to customize them in future steps.
2. Practice building and customizing monsters. In my opinion, a good encounter/monster is based on a cool concept. As coolness is subjective, I won't try to discuss it here. However, if monster = concept, then concept = base creature + template(s) + class levels. You got the gist of creatures, templates and classes in the previous step, now you simply have to put them all together. Think about a concept and try to translate it into a stat block. Start with simple things: humanized manatees, a samurai version of Yamata no Orochi, a creature you killed in the last RPG game you played, etc. You don't have to use all of those in one of your campaigns, but putting lots of stat blocks together really helps speeding the process up and understanding what a monster essentially is (a cool concept with some numbers attached). As such, try to build a monster a day until things get smoother. In my experience, casters tend to be harder to build, if only because you have to select all the spells... So you might want to start with mundane creatures before you get to Wizards/Druids/Clerics/etc.
3. DMG has a table with NPC's WBL at the end of all those table of pre generated NPC (I can't give an exact page number because I lack an English DMG, sorry). Here (http://www.d20srd.org/srd/treasure.htm#usingTheTreasureTable) is a table with treasure by CR listed for creatures without class levels (i.e. a treant, as opposed to the local Wizard that should instead equipped as an NPC). I'd suggest to not bother about rolling for random treasures because most of the time you'll have a concept already in mind and it'll be easy to come up with magic items and such that fits the theme you have in mind, but YMMV.
4. It's always funny to mess with TV Tropes's Story Generator (http://tvtropes.org/pmwiki/storygen.php) when dealing with one-shots and mini campaigns, if only to came up with crazy ideas. Pitch Generator (http://tvtropes.org/pmwiki/pitchgenerator.php) is even crazier, but maybe too much.

Somewhat unrelated, I thought you were going to ask about how to run a tutorial campaigns for new players before going into the "serious" campaign so that they can familiarize a bit with the system. I did that with my uni group and threw them in Rotut, an expy world of Kanto from Pokémon Red: they played up to the 1st gym over the course of two sessions.

[Crake]

I'm a fairly creative guy and coming up with plot twists, story arcs, and setting up an intricate and interesting world come relatively naturally to me

You'll find that GMing an RPG is very different from writing or telling a story. These things should develop organically, not be pre-planned. While the above sounds like important tools for a GM, improvisation and the ability to maintain continuity are much more important. You'll hear the sentiment here echoed that there should never be "the story". Don't plan what is going to happen. Design the antagonists, what are their plans, motives, and be prepared to have them react to the players' actions which will inevitably throw a spanner in their cogs. A good DM will have plans, but not a pre-determined story. When the players realise they can actually affect the outcome of the world around them, those will be the memories that stick with them for years to come.