First things first, choose a niche. You should choose something which interests you, you don’t mind learning about, or have the ability to pay someone else to write about. Consider the potential costs carefully before delving into something which you know absolutely nothing about. Another important aspect is to be confident that it will be a lucrative niche to work in. There needs to be an abundance of products to promote, and the commission levels need to be significant enough to give you a good profit each time a sale is made.
I would like to add that for information products, a lot of the time it’s pretty easy to rank for “information product review”. I recently did a review of a popular ebook that is a month long discipline program. I went about it by doing the actual program and documenting everything. At the end of the month I wrote up a 2700 word article summing up the whole experience.
One great traffic driver for me has been my new Travel Resources page. I put it up less than a month ago, created some pretty pins for it and it has done superbly well on StumbleUpon and Pinterest (racking up over 1.5k repins). This boost in traffic has helped substantially increase my conversions for Amazon, which was not a huge earner for me before. So, traffic + affiliate links = happy money dance.
If you would like to take a more subtle approach, include a product or service from your company that relates into your blog post. For example, let’s say that you are a wine connoisseur and that is what your blog is based around. In any post that is enticing your readers to open up a good bottle of Merlot or what have you, it would be wise to embed an ad for a quality, easy-to-use wine opener, wine glasses or stoppers that keep the wine fresh.
And what about joining another company's affiliate program? It's all about extra revenue. Think about your customers' needs: What other products or services would interest your site visitors? Join those affiliate programs. Affiliate programs can increase your sales with no upfront cost to you. It just takes a little time to plan your strategy and select the partners that will have the greatest impact on your business.