[3.5] How to setup a balanced encounter?

[Gale]

I have a difficult time creating balanced encounters for my campaign. Most of them tend to result in players becoming incapacitated and nearly dying. Actually, the entire party dropped once except for the Cleric; and that was only because I misunderstood the rules for mage armor and could barely touch him. (I thought mage armor stacked with his regular armor. He had an AC of 25.) My main problem tends to be that I over-speculate what the players can handle. However, when I try to plan future encounters to be easier they steamroll straight through them. Finding a proper balance is actually really difficult. I’ve had a couple encounters that felt balanced but it’s certainly not the norm despite my efforts. Does anyone have any advice?

[ericgrau]

Use CR and encounter level as a rough guideline. Avoid 3.0 monsters since their CR is a worse guideline. Start with EL = party level. Gradually increase up to EL = party level + 2 or 3 if needed. Always play monsters at their best to keep them from varying too much: have them hide and ambush, use the terrain, and focus fire on the most vulnerable player. If that's too dangerous then lower the EL rather than going easy on them. Otherwise after spreading out attacks for example you might have them all fight one strong foe who has little choice except to knock out a player in one or two blows. Or a tricky foe made to fight with brute strength instead of tricks may seem too easy but then you send in a higher CR brute and suddenly it's too hard.

Also know your party's weaknesses. If none of them has any ranged weapons, drop the EL 1 or 2 when using a flying foe with ranged attacks. But do put them against such foes until they learn to cover their weaknesses and that way there will be less foes that accidentally kill them.

Actual difficulty may vary but you can at least ballpark it this way. Only way I can think of without tons and tons of math or tons and tons of test fights. Though I suppose you could google which monsters people think are too high or too low of a CR. A lot of people think dragons are too hard for example. When I looked into the numbers in depth on some dragon I think I figured its CR was about 1 too low. I suppose part of that may be so that you get more treasure and less experience, but it also means you have to be more careful about not wiping a party with one.

[Troacctid]

Make your monsters stronger in defense than on offense. Avoid monsters that have lots of attacks or do lots of burst damage; instead, use monsters that deal damage in smaller chunks and have enough HP and AC to survive to do it over multiple rounds.

[Lerondiel]

Make your monsters stronger in defense than on offense. Avoid monsters that have lots of attacks or do lots of burst damage; instead, use monsters that deal damage in smaller chunks and have enough HP and AC to survive to do it over multiple rounds.

Agreed. Nothing harder to balance than sneak attacking/charging/pouncing/breath weapon/spells that have combat all but resolved one way or the other in the first or second round.