It is a very good idea to use different product promotion strategies so you can figure out what is working and what is not. Try to do split testing and measure the performance of each campaign then take actions accordingly. Changing a few things here and there can increase your profit dramatically. Make sure to place the banner ads on different areas of your site’s pages. Some positions will make the ads more noticeable than others.
Always disclose your affiliate relationship. Most visitors will probably understand that graphic ads will lead to your getting paid, but if you write a review or use an in-text link as a recommendation, you want your readers to know that may lead to compensation as well. This ensures you retain transparency and trust with your readers, but also, it's required by the FTC's endorsement rules.