#1 Do a good job of describing the product you are promoting - if you simply put up a banner ad for your affiliate marketing link, you aren't telling the visitor anything about the product, so they are much more likely to simply ignore the banner. When you actively promote a product it shows you have not only use the product but you know something about it, and that builds confidence in your audience, so they are far more likely to click the link and make a purchase.
#2 Share your product experience - when you're describing the product you are about road it is important that you share your experience with that product. The more information you can provide, the more likely a visitor is to buy that product. If you can provide graphs and other statistical data that will help your visitor to better understand what you are offering. When you believe in the product you are selling, you are far more likely to have success selling that product.

#3 Don't promote more than two of the same type of products - if you promote to many of the same product, your visitor will have a tough time believing that you think all of these products are wonderful, especially when they are all similar. The more products you are promoting the less believable you become. If today you are recommending product B, and tomorrow you are recommending product C, then a week from now you are recommending product D, and all of these products are very similar, your visitor is going to have trouble trusting in you that all of these products are so wonderful. 

The more products you are promoting, the harder it is for you to choose between them as to which you will promote. When you stick with the same couple of products, over time your visitors begin to realize that there is something special about these products since you keep recommending them or referring to them. That’s the way to create customer loyalty!

Promoting products through affiliate marketing requires you to take the time to research each potential affiliate and create the best match for your niche while offering a quality affiliate product that generates a decent commission for you. Don't just grabbed the first affiliate that seems appealing - do the leg work, read reviews and see what others have to say about this affiliate, check commissions, and research demand - then make your final decision.