If you're going to self-publish this won't help you much but if you've found a publisher who wants your book, there are several things to look at.
If a large publisher wants your book, your best bet is to have an agent who can look over the ins and outs of the conract. You could also find a literary attorney to look at the contract. Know that there are things you can change and things you can't but having a guide will help.
If you've found a small publisher, there are things you need to study. Most small publishers will ask for ebook and print rights to produce your books. There are things like audio rights, foreign sales and movie rights to name a few that may or may not remain with yours to produce. At one point, a number of small presses only took electronic rights. Having an attorney may be a help. Also a help is other authors you know who are with small presses.
Study your contract and if you don't understand some of the features, ask someone. It's rather exciting to receive a contract but if you don't know all the ins and outs, you may sign away something you would rather not have given the rights away.