Ok firstly your going to need to go to your computer and open two windows:
1. Google.com
2. inventory.overture.com
What we are looking for and what we really mean by a niche market is a market that has a relatively low number of pages already listed in the search engines. This figure represents supply or ‘competition' for this niche. What we also need a niche to have in order for us to be able to profit from it is a relatively high number of ‘demand' or people already searching for this niche.
As in basic economics a high demand and low supply creates value. So, if we can find a niche (meaning a keyword) with these qualities then we stand to profit from it.
To find this information you can look to Google to find the results pages and Overture Keyword Selector to find the number of searches the word has per month.
Ok, so how do we know what is high demand and low supply? Great question! Once you start to have a look around you will get a feel for what is a lot of searches and what is a low number of results pages.
Different people have different definitions in terms of numbers of what is a niche market and what isn't. Generally if you can find a word that has over 10 000 searches per month and 2 million or less results pages in Google. You will have a pretty solid Niche.
To give you an idea to get you started here's an example: