The two most important tips for giving a successful party:

1. Relax, drink a couple of glasses of wine, or do whatever relaxes you. If you are uptight, your guests will feel it and it will have an adverse effect on the party atmosphere.
2. Arrange the furniture so that everyone is within comfortable talking distance. This will help conversation to flow freely.

If you do these two things it will not matter what you serve, etc.,the guests will just naturally "party"!