Take 4 steps to get an understanding of an industry or market.
Look at the websites of the largest companies in the industry. If any are public companies, look for the Investor Relations section of their website where you should find financials and presentations to analysts. The financial statements should contain the 10-K or if they rework it, financial footnotes. These will talk about challenges to the firm and to the industry. Look at any presentations there and see what challenges they are focused on.
Go to Business Source Complete (the Ebsco business database) and look for a large company in the industry. On the right hand side of the results page, click on the name of the company. That will give you a quick description of the company. At the bottom of the company summary will be a section called "industry". Click on that and you will get the NAICS code for your industry (North American Industry Classification System). Click on the most appropriate NAICS code. On your left you can select "Industry Reports" and you will get any reports about that industry. You can get reports by country or globally. You can get US reports with financial ratios and counts of how many competitors are in the industry by state and by size.
Go to Mintel (the marketing database). Mintel is about consumers and products, so company names are less useful here. Try entering various versions of your product or service name (e.g. beer instead of Budweiser, Anheuser Busch, or AB InBev). Each Mintel report will have a section assessing the size of the market and a forecast of possible growth or decline.
Additionally, it is good to keep up with the news. Try checking the Wall Street Journal or use Proquest Central or ABI Inform Global (the Proquest business database) to access a large number of newspapers and trade publications (journals for specific industries).