In the business of affiliate marketing there is so much to learn, read and ask questions about and there is so much information out there. It is very easy to get caught up in the learning process and never actually put anything to use. BUT
Nothing can beat hands on experience in really understanding this business.
First, you can do all the research and learning in the world but unless you put it to use you will never really know HOW TO DO IT and fully understand it until you DO IT.
Second, in actually applying what you've learned questions come up that otherwise wouldn't and so you gain more knowledge and are able to move forward.
Third, I used to worry that if I didn't grab every possible piece of info and aspect of affiliate marketing I wouldn't be able to do it. WRONG! Most of the things I learned did not really register when reading about them "in theory." But they did register when putting them to use "in practice." That's when things start to click into place.
Fourth, Affiliate Marketing is a business of trial and error. Afraid of failure? Who isn't? But, like many other things in life it's from the failures that you learn the most. So just DO IT, then tweak it and DO IT again, and the experience of this will be the biggest catalyst to success.
Also an important thing to keep in mind is the beauty of this business is the risks are so minimal. You don't need thousands of dollars in start up costs, in fact you can do this business with ZERO start up (ie: article marketing), so you have nothing to lose and only experience to gain!
When you realize that there is nothing to lose, than the fear subsides. DON'T let the fear keep you from becoming the next affiliate marketing success story. Remember, all the "gurus" of affiliate marketing once sat at the computer not knowing where to begin, and it was the risks they took that led them to the success and wealth they enjoy today.
So put to use something you've learned, like article marketing or what ever you feel comfortable with (follow the guidelines from whatever sources you're using) and just DO IT!