It depends what you mean by rich... let's say your talking about investment banks that sort of corporation level stuff.

At that level there are people who's whole job it is to watch a portion of the world (so a guy might be responsible for Tech companies in Europe, another guy for Pharm in USA). That person is responsible for giving price targets and recommendations for companies in his area. He'll do that by looking at federally required filings, balance sheets, income statements. Usually the title is some sort of "____ analyst". He'll call into earnings calls and often will submit questions. There are also ratings companies that do their own grading that the analyst will watch. The'll also have an eye on upcoming IPO's. To us mere humans it can seem like IPO's are announced out of the blue - but really they are announced very widely by the banks helping to make that first IPO offering. There are interesting deadlines and able-to-sell dates for IPO's so that is a whole nother bucket of fish.

For mere humans... I got interested years ago as a teenager. At the time I knew maybe a dozen companies - things like Coke, Exon Mobile, Walmart - because these were household names. I started doing fake portfolio challenges - http://www.marketwatch.com/game/ is a nice one. These fake portfolios (called paper portfolios) are nice for learning because there is no money involved. If you want entertainment over actual advice you can watch Mad Money and the like on MSNBC.

Eventually I ended up picking my investments based on feedback from a group of friends. We all got together and sort of voted on what we thought was a good idea. That's worked pretty good for me. Just yesterday I made a sub, r/rvinvestmentclub, to launch the idea to the reddit masses for all to enjoy. In my little circle of friends it meant I heard about a lot of companies I hadn't considered. I'm hoping the same pleasant dialog and education happens over at my subreddit.