Because there are no disclosure requirements for private companies, it can be difficult to find any information about them. 

Your best bet is to cast as wide a net as possible, using the following search strategies:

1. Use ABI/Inform, Business Source Premier or Factiva to find articles about the company.  You may find a profile of the company in a trade publication or in a local newspaper.
2. If the company is a startup, search Pitchbook for profile and investment information, as well as similar companies in the space.
3. If the company is large or multinational, check Capital IQ (available in the Finance Labs at Rotman, IMI (UTM) and Management (UTSC)) as they may have some non-financial information. 
4. Google - check for a company website, LinkedIn page, news articles, etc.
5. Contact us if you're really stuck.

If the company was previously public but has gone private, you can still access their historical public filings from when they were a public company. Check Mergent.