Once you have used the product, you are then able to write a review that tells your customers or visitors what you liked about it and how it helped you. A personal recommendation will sell more than any advertisement. Your advertising message will produce a stronger response from people that already know and trust you. Therefore, your own opt in list or ezine is going to be more effective than your web site at generating commissions. If you don't have a means of staying in contact with your customers or visitors, you are severely limiting your income producing potential.
Banner links on web sites are less effective than text links.
More people will click on a text link than a banner. With text links, you are able to pre-qualify people before they visit your affiliate partner's site, and you will find that more convert to sales. To supplement your promotional activities, consider advertising that gets people to visit the details of the affiliate program on your site, or alternatively, sends them direct to the affiliate site using your affiliate link. Paid ads in ezines can be relatively cheap and can provide you with highly targeted prospects for your promoted product or service. Many ezines accept paid advertising.