You must pick a product or service to promote. Here is the trick, find out what people are searching for, what problem they need solving that has the little or no competitors, and you have found a niche market that you can dominate. Now place yourself as an expert, in front of them, in that field, and you are on your way. There are plenty of ways to do that article marketing, search engine rankings, blogs, classified adds and so on.
There are a few good programs that can help you find that niche market. An example of this would be something like golf. Now if you were to search the term golf, you'll find it to be a hige market, to much competition. Now you have to dig down within that market and find something like 'how to cure your slice' and that may be a niche market that you can now compete for. Always dig to find that micro niche market.
Now here it is, the single biggest mistake that affiliate marketers do to sabotage their efforts and kill their chances of success. If you have been around internet marketing at all, you have certainly heard the saying The money is in the list, well it is absolutely true. According to research, the average person will need 5-7 exposures to something before they will buy it. So if you are simply sending customers through your affiliate link to the companies website or sales page, then you are leaving a lot of money on the table! You must collect, at least their name and email address in order for you to start building a relationship and credibility with your customers for long term results.
Collecting their names is as simple as having a squeeze page. A squeeze page just squeezes their name and email address information. In return for their information most will give away a free report or ebook on what ever topic is relevant to your customer. Make sure when you give out this report or ebook, or what ever you offer, you must over deliver on it. What I mean by that is this: everyone offers something for free nowadays, so your offer must have good solid information for them to use and benefit from immediately! Especially on the very first exposure your customer has of you. This is the start of building that solid base for the future relationship that you will be developing.