One of the first things I always do to check out the potential of a niche is to look for Google Advertisers.
If there are people bidding on niche-related keyword phrases, then that’s a good sign that there is some money in that market. If there are no sponsored ads, then that’s a good (or bad) sign, that there is no money in that market. And usually, the more advertisers there are in that market, the more profit potential it has.
Most people do it the slow way: they just type in the search phrase in Google and see if on the SERPs (search engine results pages) there are any ads showing up.
But not you anymore. Instead of going to www.google.com, you go to www.google.com/sponsoredlinks.
This is a search engine specially for AdWords ads. Just try it out. If you have previously been researching ads via the normal google search, you will find this special adwords search very useful, because it can save you a lot of time if you do a lot of research.
Now, if you don’t have a niche research tool, you have to do this by hand. But I really recommend that you check out my Market Samurai review, because I think it is a great piece of software for most online marketers.