I think this is very dependent upon the individual trader.
However, I believe the vast majority of individuals will perform better if they have and follow a strict system based on a clear set of trading principles. I say "principles" because most people unconsciously don't like to follow "rules".
I further believe the system should use as few principles as possible and as few data sources as possible. That is, not a lot of charts and a lot of indicators. There is a thread discussing "simple is better?"
The best one I've seen uses only one chart, two indicators and a MA.
I used to use all kinds of stuff and love to trade, until I lost over 100K, now I love to trade because I make a lot of money and use no stuff!