I've found that if you spend some time with affiliate marketing (where you earn commissions by referring readers to products you like), you can make much more than you can with traditional advertising, for the simple fact that traditional ads just don't work that well. Click-through rates are low, so the advertisers can't afford to pay you all that much to run their ads.
But when you recommend products you love (genuinely, of course), conversion rates are much higher. By doing it tastefully and in moderation, you can make affiliate commissions a significant part of your blog's income.
Warning: U.S. law now requires that you disclose it to your readers when you recommend a product for which you'll earn affiliate commissions. (Not that you'd want to trick them anyway, I hope.)
Here are affiliate programs I've had the most success with:
1. Amazon.com – Amazon is easy to get started with and the best thing is that have so many products. Anytime you mention a book, a piece of fitness or cooking equipment, or even food, you have a chance to use your affiliate link. Even better: if someone clicks your link to check out a product you mentioned and buys something else, you still make money.
2. iHerb.com – iHerb.com is an online health food and vitamin store. Their "Rewards Program" is a little different, because they give you a coupon code that you can share with readers, entitling them to five dollars off their first purchase. When readers use your code, you earn a commission. Even better, if any of your readers have blogs and get their own codes, you earn commissions on their sales as well, and so on for two more levels! The downside is that you need to buy something to join the program, but you can just get something cheap and use my code RAZ652 to get five dollars off the cost, if you've never bought from iHerb before. (Note: I'll earn commissions on your sales if you use my code. See, disclosure is good.)
3. iTunes – Surprisingly, iTunes has been one of my best-paying affiliate programs. I say "surprisingly," because you only earn a few cents per song that sells. But if you've ever been on an iTunes rampage where you can't tear yourself away from buying songs, then I supposed it's not all that crazy that you can rack up sales pretty quickly. The iTunes affiliate program is managed through LinkShare, where you can sign up for free. (I get a commission for referring you to this too.)
And of course, there's my affiliate program for No Meat Athlete shirts.
