1. Looked up what reports a company has to file. The key one I liked is 10-Q.
10-Q: (from investopedia) A comprehensive report of a company's performance that must be submitted quarterly by all public companies to the Securities and Exchange Commission. In the 10-Q, firms are required to disclose relevant information regarding their financial position. The form must be submitted on time, and the information should be available to all interested parties.
2. Look up your favorite public companies 10-Q. For me: Google's 10-Q filing => http://www.sec.gov/Archives/edgar/data/1288776/0001193125072...
3. Get a book like Brealey, R., and S. C. Myers. Principles of Corporate Finance. 7th ed. Irvin McGraw-Hill.
4. Using 10-Q, book, and google, go through each line of the financial statement to figure out what it means.
5. For some insight and wisdom, look at Warren Buffet's letters to investors. => http://www.berkshirehathaway.com/letters/letters.html
enjoy!