Google Adwords can be used to drive targeted traffic to a sales page. You simply make an ad in your adwords account then use your affiliate link in the target page URL of the ad. Obviously, you will have to continuously measure the conversions and see if the campaign cost is less than the campaign profit in order to keep the campaign running but I am sure you get the idea.
#1. Wealthy Affiliate - Wealthy Affiliate is my top choice for anyone interested in learning how to create an online business. The training is the best out there and websites and hosting are all included in the program. They also have a free option to join without a credit card so that you can see what is available in the program before you purchase.
The problem with affiliate marketing, like many other home business options, are the so-called gurus and get-rich-quick programs that suggest affiliate marketing can be done fast and with little effort. Odds are you've read claims of affiliate marketing programs that say you can make hundreds of thousands of dollars a month doing almost nothing ("Three clicks to rich!"). Or, they suggest you can set up your affiliate site, and then forget it, except to check your bank deposits.