If you are a music lover, it would be a good idea to promote it over books and even other products. All you need to do is listen to clips of a full album within a short period, say 10 minutes, get a good feel of it without you purchasing it and do a short review. If there is another niche you are passionate about, make sure you get a unique discovery about it. Of course, there are hundreds of thousands of reviews about these products all over the web but you need to make yours more unique to attract people to your site.
Once you have the affiliate links you need, it is time to present them to your audience. As you start using affiliate marketing to talk about products, you need to be aware of how your audience perceives you. If your website appears to be only after their money through an overwhelming amount of affiliate links, then they are more likely to simply leave your site.