What do you want to earn? Is this just a little bit of side income on your hobby blog or are you trying to replace your full time income? If you’re trying to go big then you’re going to want to focus on more high-quality products with big commissions.  Maybe you will be building your site or blog around the specific product you want to promote, like a product review or comparison site.
Education occurs most often in "real life" by becoming involved and learning the details as time progresses. Although there are several books on the topic, some so-called "how-to" or "silver bullet" books instruct readers to manipulate holes in the Google algorithm, which can quickly become out of date,[41] or suggest strategies no longer endorsed or permitted by advertisers.[42]
Who can tell me if “link masking or cloaking” is a violation of the Google TOS? I think it is and I see dozens of affiliate sites doing it. I also see quite a few sites not using “nofollow” on their affiliate links. Unless your masked link says something like “I bought product X used in this review at Amazon.com” it would be a violation. I think if reported, you’d be in for a manual spam action against your site. Thoughts?

Online affiliate marketing is wide open. You can write about or promote whatever you want! However, the incredible amount of possibilities can be overwhelming, and that leaves a lot of people saying that they don't have any good ideas. There are literally hundreds of comments below saying “I don't know which topic to pick”, or “I don't have any hobbies so what should I do?”. (Get help picking your topic here)
Great article as always. As far as finding the right keyword phrases, what I’ve always been unsure of is where and how often do we use these keywords? In your example, “sleeping bags under $100,” would I place that in my post titles and/ or content? How often is ideal to still make it look natural? Could I use that keyword phrase again on other articles/ reviews? Thanks for what you do.
If you can’t imagine becoming a mattress expert, then perhaps you should just pick another niche! There are millions of options related to mattresses that you could focus on instead. Some topics that would be less resource-heavy could be “how to get a better night sleep”, “how to become a morning person”, “natural alarm clock reviews”, “hypoallergenic bed linens”, and many more.
I want to do an “inspirational” post to help newbies see that affiliate marketing is a long-range game plan, not a “get rich quick” scheme. Looking for those willing to share how long it took to get the first affiliate sale and a bit of insight into how you did it. Of course, your name and your website/blog link will be included. You can share it here, or email me.

In 2006, the most active sectors for affiliate marketing were the adult gambling, retail industries and file-sharing services.[21]:149–150 The three sectors expected to experience the greatest growth are the mobile phone, finance, and travel sectors.[21] Soon after these sectors came the entertainment (particularly gaming) and Internet-related services (particularly broadband) sectors. Also several of the affiliate solution providers expect to see increased interest from business-to-business marketers and advertisers in using affiliate marketing as part of their mix.[21]:149–150