What is your business? If you say "Shoes!" do you mean you want to manufacture shoes or do you want to set up a retail shop? These are two different industries and if you intend to do both you may want to do a search on each industry separtely. Some questions to ask:
What is the NAICS code for your industry (see the next tab)? Find out, it'll help you with your research.
What are the current and historical trends in the industry?
What are the financials for like businesses?
Also, the industry you want might not exist. For example, if you are selling organic baby food, you might find industry trends for baby food but not for organics specifically. You may need to do a separate search on organic food trends.
Next, ask yourself...
Are you marketing this product or service to a particular region? Are you selling it online? Once you have an idea about that, it leads to some questions:
Are there your competitors in the area? Who are they?
Is there specific region that you should concentrate on?
Where are other businesses in the area?
Is the market already flooded?
Since different regions have different demographics it leads to the next question...
Men, women, seniors, teenagers? Who do you think is going buy this product or service? Questions you might consider: