An event such as a launch party for your new book is all about details, but you shouldn’t need to become so immersed in them that you can’t enjoy the show. One way to assure that is to find sufficient help.
Salesperson. It is essential to find someone you trust to handle your book sales so that you are free to mingle and do your sales pitch. You shouldn’t have to be distracted by worry about what might be going on at the cash register. The day is more or less about selling books, but the farther from the money exchange you are and the more relaxed you seem, the easier it is for attendees to interact with you.
Music. Some sort of music will fill in the gaps when you are not reading, presenting, or otherwise engaging the attendees. If you are lucky enough to have a friend who sings and is willing to help out, that is the best of all worlds. Your friend will take attention away from you for large chunks of time and allow you to mingle freely.
A Door Prize or Raffle. I raffled a bottle of wine. Not an expensive one, but a bottle that you win somehow seems more special than one you purchase, regardless of quality. The raffle keeps people at your event until the designated time for picking a winner. The longer people are at the event, the more likely they are to buy a book. There is seldom a lack of volunteers to pick your winners for you.
Food and Drink. I held my book launch at a winery. It goes without saying, then, that wine was available for purchase. We did supply non-alcoholic beverages and finger food (pretzels, chips). Because I launched at a winery, it was an inherent symbiotic relationship and of course the winery was pleased to help supply the food and soda.
Schedule. It is important to have a clear of idea of what happens when, not just for the author but also for your helpers. Even though it is most likely that you will need to ditch your schedule before the first hour is up, due to unforeseen circumstances, that is not always the case. And even when it is, having an idea of the sequence of events makes it much easier to “punt” when necessary.
Enjoy the Party. Finally, the most important ingredient is fun. This is a party! You should enjoy yourself; bask in the honor and the sunshine, rise to the occasion. When your guests see you enjoying yourself, they will as well, and that’s when good things happen.