Basically, a book launch party is a book signing/reading with the added benefit of being fun - and newsworthy. A book launch party is an ideal opportunity for promotion, so don't waste it! The release of a book, especially a book by a local author, is considered news, which means you can get press coverage. It is also a great way to meet your fans, make new ones, and to connect with people who share your interests.
Tips on making your launch party a success
1) Plan ahead. Like all events, a launch party requires planning. Where will you hold it? Who will you invite? How will you advertise it? All of these considerations require planning at least three months prior to the release of your book.
2) Pick an appropriate venue. Bookstores are great places to hold launch parties, but there may be more appropriate venues, depending on what you've written. For example, if you've written a book for children, you may want to hold your launch in a children's museum. Libraries can also serve as good places for a launch party, particularly in larger cities. Consider a restaurant if you've written a cookbook, or a recreational supply store if you've written about the great outdoors. (One of the advantages to holding a launch party in a store is that they may be willing to carry your book.) Make sure to contact your venue several months in advance.
3) Advertise. Once you've picked a date and a location, contact local media. Ideally, you should send a press release. You can also call the appropriate editor (e.g. local news). Don't forget to list the event in your local media (newspapers, TV, radio). Do this well in advance. News media have submission deadlines that are often two months or more in advance of an event.
4) Invite friends and family to spread the word. Facebook is your friend. Tell everyone on all your social media about the party - even if they live in Zanzibar. (Assuming you don't.) Getting the word out is important, because it creates buzz.
5) Send invitations. This is a party! Send invitations to everyone you know, and to a lot of people you don't. Anyone who you think might be interested should be invited - that includes other local authors, publishers, and people who are involved in professions related to your topic. Invite local educators if your book is for children; invite health care professionals if you've written about health (or illness); invite local coaches or athletes if you've written about sports. A party is the perfect way for people of like mind to mingle. They will have a good time talking to one another, and you will make some contacts.
6) Prepare an EVENT. If the venue allows food, make sure you have something tasty for people to eat. And don't forget the music. If you've written a children's book, have some activities planned for children. Part of the event is your reading, so make sure there are chairs for people to sit on.
7) Dress to impress. On this occasion you are the belle (or beau) of the ball. Wear something memorable, and in keeping with your genre. (If you've written a thriller, sure, go for black. Otherwise, something that makes you look authoritative and/or friendly.) Anything that makes you stand out in a crowd will do. You will be photographed!!
8) Don't forget your books! If you are reading in a bookstore, they will prepare a display. But in non-traditional venues you may have to make your own. Make sure you have plenty of books on hand. It doesn't hurt to think about how you are going to sign them before you actually pick up your pen. (Enjoy! is good for fiction.)
9) Piggy-back. If there is another large event being planned, it may be worthwhile to approach them with the idea of combining forces. This will help you cut costs and save a lot of work.
10) After the party. Make sure you take lots of photos (and videos) to post on your website. Tell the whole world about your successful launch!