What's your worst mistakes you have made during character creation?

Mine are having the skill Dragonish as a major skill and having a phobia to undead on the same character. At least the phobia (and a low tolerance to disease allows me to have some good advantages (expertiste in long blade, bonus to hit against daedra, rapid healin in light and 1.5X INT magic).

The first time I played the game I thought I was a good enough RPG gamer, so created a character from scratch.The problem was he couldn't wear or use iron, and on game start I got an iron sword and iron cuirass! Didn't think i'd get very far with just my fists and no armour, so I quit and went for a standard character so I could start playing!

Misspelling anything.

Hex editors FTW!

If you go to your character sheet (hit F5) and click on your name, you can edit it. Can't remember if you can do that with your class or not.

Picking one of the premade classes LOL

Well, mostly because they have way too many melee skills. Matter of fact, picking more than 2 weapon skills was a mistake I did fairly often.