We've been through the big points in asking for a raise, including how to approach your boss, maintaining confidence and poise, and how to prepare for an effective negotiation. One fine-tuning point is the way that you should actually put your desired raise into numbers: Ask for a particular percentage raise, not a specific dollar amount.
Telling your boss this number is probably the thing that makes you most nervous about having the conversation in the first place. Get through to your boss by speaking her language: Whenever I've been informed of a raise, it's always been presented as a percentage. Dealing in percentages makes it easier to negotiate and sounds more professional than dealing in dollars.