Taken from a post by Mithdradates, I thought this was excellent advice on planning/creating a build:
Rule 0: When in doubt, make the choices that are fun for you. Power is good and fine, but in the end you are playing the build and what feels right to you is going to be more enjoyable and, because it meshes with your playstyle, easier to play.
Rule 1: Know your environment. Know what equipment and immunity items are available to your character and opposition before you build your character. If you can get an immunity to critical hits item, then a palemaster is less appealing. If immunity to mind spells is common, don't specialize in enchantment spells. If true seeing items are common, shadowdancers become less attactive, etc. Also be aware of potential imbalances in your setting before you play. If you're planning to play on a PW where true seeing has been changed to not automatically identify hidden creatures and shadowdancers have not been banned, either play a shadowdancer or find another server.
Rule 2: Break down your build into a list of must haves and nice to haves. The must haves are the things that define your build, it could be feat like devastating critical or it could be requirement like an AB of 44+ to hit the monsters reliably on your server. The nice to haves are things that would help your character survive but aren't necessary, e.g. improved knockdown (probably a must have for a rogue build, but a nice to have for most melee builds). Work out what you would need to fit in your must haves. If you find you need to min/max to get those in, you're being too ambitious, you're over extending your build and you're suffering in other places. Once you have put in your must haves, try to fit in as many nice to haves as you can.
Rule 3: Be critical of your build. Once, you've fleshed out your build ask yourself if I was going to take down this build how would I do it? What is its weakness, does it have low hitpoints, low saves, low AC? Against what AC is it going to have trouble hitting, and how common are those enemies? What SR is going to mess up my casting and how high does an opponent's saves have to be to avoid my finger of death? Once you've figured out your weaknesses, modify your build as much as possible to minimize those weaknesses. This is where knowing the immunity items available in your setting can be handy. You should be your build's worst enemy.
Rule 4: Test your build. You can calculate most things by hand, but there is nothing like building it in an editor to see weak spots and potential calculation errors you might have made. Sometimes this can reveal places where you can change the order that you level up to make your build more playable.
There is a lot more to say, but that should be enough to get you started. _________________ This signature will self-destruct in 5 seconds...
This is good. Way to go Mith! _________________ "With Europe liberated, the people of the world turned their attention to that old devil, the United States of America [...] We taught that monster of old the true meaning of freedom." Star Wreck