The products and services you will be promoting to your audience must be relevant and good quality. Make sure you believe in them and know everything about them, because this will be crucial to you delivering the sales pitch to your audience. You need to build trust with your audience so make sure the products and services you choose to promote are trustworthy enough.
Some advertisers offer multi-tier programs that distribute commission into a hierarchical referral network of sign-ups and sub-partners. In practical terms, publisher "A" signs up to the program with an advertiser and gets rewarded for the agreed activity conducted by a referred visitor. If publisher "A" attracts publishers "B" and "C" to sign up for the same program using his sign-up code, all future activities performed by publishers "B" and "C" will result in additional commission (at a lower rate) for publisher "A".
Mechanical Turk: Amazon's Mechanical Turk is a resource for doing human-intelligence tasks, or as the site commonly refers to them, HITs. You get paid a very small fee for any given HIT and you'll need a good deal of volume to make a substantial amount of money. But it is a resource you can use in your spare time to generate a small income online.
Better yet, you can even upload your own book to one of the world’s largest book sellers: Amazon. With Amazon self-publishing, you set the price, retain the rights to your book, and get access to Amazon’s massive audience. For every sale, you keep 70% with Amazon taking the remainder as a fee. If you want to get started, check out Leslie Samuel's great guide to selling eBooks online or follow Tara Gentile on CreativeLive as she shows you how to use your existing body of work to write an eBook within the next week. Who knows, you might just write one of the best business books of this year!
Always disclose your affiliate relationship. Most visitors will probably understand that graphic ad will lead to your getting paid, but if you write a review or use an in-text link as a recommendation, you want your readers to know that may lead to compensation as well. This ensures you retain transparency and trust with your readers, but also, it's required by the FTC's endorsement rules.