I think I've touched on NPCs in the past but here are some points to remember for those NPCs you need for your adventures:
1) Have a list of handy names for both girls and boys, and if you are really inventive, make sure you have names for different races as well.
2) A list of quick descriptions and equipment can never hurt. Players like to hear what someone looks like to make snap decisions about how good or bad a person is.
3) For major NPCs make sure to have name, description, equipment lists and even some background to help you with interaction with the players. If they are to be major players you want them to make a major impression.
4) Keep track of your NPCs. I had a player who loved to talk to that barkeep or traveling bard when ever they met again and he knew exactly what they looked like and their names. Players never forgive those mistakes.