I personally prefer to do it that way--you can create a more convincing review that's more likely to make sales. It's not always possible or practical, though; for example, would you break up with your significant other just to test a product for getting your ex back? ;-) In cases like that, or if the product is expensive, it's usually best just to use the vendor's affiliate resources instead.
Many affiliate marketers use paid advertising to generate additional traffic to their site and drive more sales. Paid advertising on social media is often a good place to start, as these networks tend to be more affordable.You may also want to consider taking out inexpensive banner ads on small niche sites. Depending on your niche, Google AdWords could also be a good option to drive some paid traffic to your site.
Banners – after testing them out I decided to take down my banner ads since they looked salesy and weren’t working like my affiliate links did. They’re easy to throw up, but distracting and probably won’t get great results. If you try them, be sure to show specific sidebar banners based on the type of content people are reading on your blog (for posts that fall under my SEO category I would show a banner related to SEO, and for posts under my website speed category I would show a different banner). You can do this using a plugin like Widget Logic.
The problem with affiliate marketing, like many other home business options, are the so-called gurus and get-rich-quick programs that suggest affiliate marketing can be done fast and with little effort. Odds are you've read claims of affiliate marketing programs that say you can make hundreds of thousands of dollars a month doing almost nothing ("Three clicks to rich!"). Or, they suggest you can set up your affiliate site, and then forget it, except to check your bank deposits.