The first, and, certainly one of the most obvious, way to research a market is to use affiliate networks like ClickBank and Commission Junction. They have thousands of different affiliate programs from hundreds of different markets, and you can basically sort the programs by profitability. I personally like to promote or sell info products rather than sell physical products.
I use Clickbank's marketplace extensively. It's a great place to research markets and choose a product to promote. clickbank.com/marketplace. You can either browse through categories or use the search feature to research your market, but I recommend you use the search feature. After you enter your main keyword, here's what you should look for in the search result.
1. At least 3 products that appeal to the market. The more the better. 2. At least 1 product that has "gravity" of at least 20. The more the better. (Gravity is a complicated algorithm that calculates how many distinct affiliates have sold the product and how recent they have sold it. But I use gravity simply to know how well the product is selling) 3. At least 1 product with $ / sale of least $ 20. The higher the better. This tells me that how much the market is willing to pay for a product that they want.
When I typed "wholesale" into Clickbank, it returned 46 products. The best selling product (SaleHoo) had gravity over 160 with $ 42 affiliate commission per sale.
If the market is good enough, choose a few products that you want to promote. Generally, look for the top sellers with gravity of at least 10. From the "wholesale" results, SaleHoo was about the only one I liked and I chose it as my main product …
Keyword Search Tools (ex. Overture, Wordtracker)
Use the keyword search tools such as Overture, Google Keywords, WordTracker, or Keyword Discovery to find out how many search queries have been used in search engines. The higher the search volume is, the greater the demand. Careful, though! Keep this in mind: high demand does not mean that you will make money.
For example, "Paris Hilton" has been one of the most frequently typed keywords, but how would you make money out of it? You can promote T-shirts or posters with Paris Hilton on it, but you only can make a few dollars at most. Beside, look at the number of Google ads. There are only two ads coming up for term "Paris Hilton" on Google.
The point is this: demand does not equate to money. So do not use the keyword search tool to find your niche, but use it to …
1. Qualify the niche you are interested in using 2. Explore your niche more deeply. Look for possible sub niches. 3. Compare you niche with other niches. The higher the search volume, the better Generally, you want the market (main keyword) you selected to be at least 20000 searches in overture and 2000 for Wordtracker.
..And The More Easy Way Is: