When looking at successful investors from the past their stock selection styles have varied greatly.
From Peter Lynch to James Cramer to Warren Buffett to George Soros to William O'Neil to Gil Morales. They're all different, yet they're all successful.
I think every successful investor needs to learn the styles of as many successful investors as they can. By doing this they are able to find a system that works, for them. O'Neil and Buffett are almost polar opposite. Yet, they have both been very successful.
I have been very influenced by William O'Neil and his book, How To Make Money in Stocks. I read it over ten years ago and sometimes it still keeps me up at night. Many call this style of investing momentum; I don't really think it's an accurate description.
When high quality growth stocks break out to new high prices after consolidating there is a very tangible 'vacuum' and prices sometimes seem to go straight up. Every great stock has seen its shares go through these periods. Microsoft, McDonalds, Wal-Mart, Baidu, Google, Apple: each in their day, traded up for days on end.
Each of these companies had very definable qualities in regards to earnings, sales, profit and debt as well as qualities related to their shares: price, volume, float, quality of institutional ownership, even volatility.
I make it a habit to try and stay aware of all the stocks in the market that have the same data points as the above stocks did, before they made their historic runs. Even if I'm not trading, I try to know what's going on. It's become like a story that writes itself every day. I don't like missing chapters.
I think different investors will find success with diffent styles.