When it comes to investing successfully, there are different strokes for different folks.
If you're interested in the methodology preached at the "GenJackripper School of Investing for Obsessive/Compulsive Anal Retentives", you'll find it outlined here on some other Yahoo threads, to wit:
ENCD; #50 through #55 and HCC; #17 through #19.
As you will note from humpbee's response (posting #21) on the HCC thread, not everyone is comfortable with the GenJackripper methodology and that is OK, too. You must develope the approach that you enjoy working with and, most importantly, that works FOR YOU!! Mine may just be a helpful guideline you're free to follow or not, as you choose.
A couple of other points.
A hand-held calculator can be a help in quickly determining growth rates or CAGRs. The one I'm familiar with and use is the Hewlett Packard model 20 S SCIENTIFIC. I'm sure there are others that perform the same function, I'm just not familiar with them.
A word about diversification. Diversification is good. Concentration in a few stocks has its points as well. You need to strike a balance between the potentially greater rewards afforded by concentration in a few companies (assuming they perform as you expect) and reducing your risk exposure through diversification among several companies (if some of them don't). While there are market mavens who can suggest guidelines, depending on the amount you have to invest, only you can decide what you are comfortable with. Warren Buffet, for example, has said that you don't need to invest in more than six different companies to make money. I recall a money manager citing an upper limit of thirteen holdings regarding diversification.
To learn as much as you can about the companies you've invested your money in is an ongoing process. The more you have to keep track of, the more time you will have to invest and the more difficult it will be for you to stay on top of things.
But, boy, can it be interesting if not fascinating, and hopefully, rewarding monetarily. Good luck to you.