I have been doing some research and trying to find out why people fail at their sites. You might say it is more important to find out what they succeed but sometimes that doesn't help the newcomer.
Usually the successes are so great that they are beyond the initial goals and possible achievements for someone just breaking into the biz.
I read this article here on what not to do.
http://www.affiliateseeking.com/ashow/61.html
Many people fall into these categories. Also, when people start out, they see everything as rags to riches which is not true. But when they start searching through the merchants' products, they focus on only high paying ones that may not meet their niche. They calculate "well if I only sell one a day, 30 days a month"
It just isn't that simple. Even when you choose products in your niche, you might not sell that much to start. Keep your affiliate links natural and relevant and keep realistic goals.