I think lots of good advice has already been given, so I'm going to echo the ones that stick out most to me: make sure you are not a drag on your party members. Find a way to make meaningful contribution in combat, and avoid being useless or a hindrance. If you can manage that, you can make the character work.

Let me provide something of an example of what not to do. Some years ago in one of those not-quite-D&D d20-based systems, a friend of mine was playing a mad scientist type character. He decided that he wanted the character to be absent-minded and sorta ADHD, the kind of character who might drop whatever he's doing no matter how important it is, because he just had a great idea and he absolutely has to write it down right now. He decided that the way to do this was go make himself roll Will saves periodically, even in combat, and if he failed whatever arbitrary DC he had set for himself, his character would get distracted and would fail to act during his turn. I cannot stress this enough: DO. NOT. DO. THIS.