Character Creation (Gods and Men Supplement)
From D&D Wiki
Advice on Character Creation
Do not be afraid to ask the DM for advice on how to make your character. Perhaps he is planning an epic adventure based on the Trojan War. For this, you and the rest of the party would want to make your characters to be on the same side. Similarly, if the DM is planning a political drama, it's best not to make a brash, impulsive barbarian.
Focus on the Party
Working together in the party is the basis of any good D&D game. Your character should fit in and integrate well with the rest of the heroes. For instance, if there are already two fighters, creating another fighter would not be the most ideal plan, as one of them will end up doing all the work.
A character should have personality. Maybe it's molded after your own, or perhaps it's something entirely different. Maybe your character is racist, or hates a certain religion. It's this sort of unique-ness that allows your character to grow, not just in levels but also in personality. This is what creates truly memorable games.
Personality and Backstory go hand in hand. Backstory is tricky: If you give your character too little backstory, he seems to be made of paper and not realistic. If you give your character too much backstory, then there is no room for your character to improve. Your character's backstory should ideally explain much of their personality.