Now that we have simplified Affiliate Marketing, you can begin to get started right away. The easiest and most effective way to do this is to choose a product a service that interests you and one you know enough information about to promote it effectively. Just think about a topic you enjoy and then do a search on "(topic) affiliate program." If you have a popular interest, you should get more than enough results to choose from.
With your choices laid out in front of you, you will easily be able research each, one-by-one, to determine which offers the best commission, the best marketing tools available and the easiest to use website, so when you do send prospects their way, the prospect can easily navigate to find what they need.
When that is determined, you should sign up for ONE program to start. Don't overwhelm yourself with multiple companies, remember, you are still learning how this process works. With the affiliate program determined, start by doing advertising ANYWHERE you can at no cost. This includes Free Classified Ads, Forums, Message Board, etc. Keep track of what results are working and continue to advertise, dedicate at least one hour/day to doing nothing but advertising.
Once you have tested what programs work, what programs are available, and get a feel for how to advertise, you can begin to add more programs to your affiliate marketing plan. You will be quickly on your way to making a good income online. Just remember, anything worth mastering takes time, allow yourself a minimum of 4-6 weeks to really get good at affiliate marketing.
There are literally hundreds of programs that will set you up in a ready-made affiliate program. Take your time and learn at your own pace. If you jump into anything without the needed knowledge, you will easily get discouraged.