Look - Does your site look trust worthy? Does it look like a 5th grader built it? Sometimes less is more and it is a trap we all fall into. A simple clean layout with a small professional logo is more than enough. Also stick to just two or 3 colors. Black, white and one primary is perfect. I have gotten over creative before. You likely have as well.
Content - Does your content make sense? Does it read right? Is it factual? I love the Best Spinner, but it can be used to the wrong way very easily to create plain crap that is unreadable. Also make sure the facts are right about a product or an article. Surfers pick up on inconsistencies very easily. You do not need to be a Pulitzer Prize winner to create simple, to the point, factual content. Use your content to paint a pretty picture and sell the product. It is not hard to do.
Ads - Are the ads you are showing trustworthy looking? Do the banners look good? Do the ads match what you are selling? No obnoxious clams? Any stats you can look at for the banner conversions inside your affiliate admin panel? This is often overlooked. Too many times we head for a banner we like and fail to look if there is one that has been converting better. It draws clicks because the surfer trust it.
Exit - Are you sending the surfer to a trustworthy site. Did you trick them to go there? Are they going to where they think they are going? Will where they are going have what they need or are looking for?