It almost goes without saying that for niche affiliate marketing you need to define your niche first. The trick is to identify an area that you are interested in, or even have a passion for, and then find out if there is a market out there where you can position your niche affiliate marketing business.
Deciding what niche affiliate marketing subject you should go for is quite a task. You want to find something that is not too broad and at the same time not too narrow. Perhaps your interest is cooking and recipes. Now obviously this is too large a topic for a niche affiliate marketing business. What you need to do is to narrow it down.
One way that you can do this is by using sites that will check out keywords. There are a number of keyword tools out there to help you in your search for your niche affiliate marketing subject. One of the best is Wordtracker. You can sign-up and have a free 15 day trial with this to get the feel of it.
If you put "recipes" into a keyword search tool you will notice that there are many thousands of searches a day. The bad news about this is you will be competing with thousands of other niche affiliate marketing sites and your proposed site would not rise to the top. This is what you are aiming at. To get your site noticed by the search engines.
Just to try it out I was idly scanning through some keyword searches and suddenly noticed that "leftover ham recipes" had 2242 searches a day. I know, isn't it amazing?. This is what you are looking for. I didn't take it further but if you were thinking of developing a site you could then do some more searches and see where the traffic is going i.e. which sites are at the top of the search engine rankings.
Then you can go on your flight of fancy. Your niche affiliate marketing thoughts might lead you to decide on a site called "Leftover Recipe Heaven" or something similar. The next step would be to source the best available affiliate leftover recipes books on the market. Now you are on your way.
To enhance your niche affiliate marketing efforts how about adding a blog, "Leftovers Tonight", you have got the idea.
I know little about cooking, it is not my passion but whatever yours is take this as an example of how niche affiliate marketing can be developed whatever your topic of interest. Ultimately content is king. The closer you can come to the words people are typing into the searches the more likely you will be to have found a niche affiliate marketing bonanza.
Search engines are just that -* search engines. They are programmed to find the most relevant sites for the search terms. The more relevant your site content the more likely you are to hit that front page. To find the ideal niche affiliate marketing business start playing with a keyword search tool around your area of interest and you will be amazed what you come up with. I was.