You may want to grab your towel, just in case.
Step 1: PLAN
The first thing to do is decide what day, time, ect. to have your party. Planning at least two weeks in advance gives you plenty of time to make all the big decisions, like who to invite, and what to wear. It also gives your guests lost of notice.
The next step is to decide what kind of party. Outdoor summer party? Pool party? Movie party? Hey guys I can't figure out a theme but I just wanna party party? You could play dirty and tell each individual something different. Tell one person it's a pirate party, tell the next it's a hawaiian-theme, ect. Then laugh your head off when they all come dressed different! I decided on a clam bake after finding a recipe.
Decide what you want to do, then.....