This encourages sales better than anything else. Use the product yourself, then tell visitors in your own words what you liked about it. Don't worry about making your copy sound professional. Writing your testimonial in your own words is what counts with prospects. Put your most promising program near the top of your opening web page.
Visitors tend to click links near the top of the page first.
Include a headline and short description. People should understand what it is your program is selling and what benefit they will get for clicking to read more. Choose affiliate programs that match the topics and purpose of your site. Try to find products and services that will interest the kinds of prospects who are drawn to your site's content. If your site provides tips for small business, an affiliate link to an office supply firm would make sense.