Cut off all contact for seven days. Time apart will help any unpleasantness become a memory instead of an open wound, leaving him open to seeing you in a better light.
Adopt a positive mental attitude. She is more likely to be attracted to you if you are confident and independent. Remember, you may have lost a girlfriend, but you've gained time to do things you enjoy. Reach out to friends, spend an entire at the beach or playing sports, and simply have fun -- without her.
Begin a diet and exercise program. Set realistic goals and workout every day. You will be pleased with yourself for sticking to the program and even more pleased with the results. Take care of yourself and you will begin to exude confidence that he will likely find attractive.
Call your ex, but don't discuss the breakup. Ask how she's been, and talk about how she has spent the past week. Keep the conversation friendly and make plans to hang out on neutral ground, such as a restaurant or park. If she doesn't agree to hang out, don't force the idea. End the conversation on a good note and tell her that you hope to hear from her soon. If she doesn't call within a week, call to ask for help with something, such as fixing your computer or volunteering at a charity event. Get her to agree to see you, but don't appear desperate.
Greet him with confidence, but display a touch of vulnerability. Don't be afraid to act silly. For example, tell a foolish joke or invite him to play a childish game. Keep the conversation focused on topics that interest him and listen intently. Don't bring up past arguments. If he brings up sensitive subjects, respond as honestly as possible without engaging in an argument, and change the subject quickly.
Use all the powers of seduction in your arsenal. Sit less than an arm's length away from her as often as possible. Playfully make light physical contact. Thumb wrestle or touch her ring during seated conversation. Focus on helping her remember why she chose to date you in the first place.
End the date on a positive and flirtatious note. Tell him you had fun, but don't try to pin him down on another date. Kiss him goodbye, but nothing more.