Pick a fund whose manager that is significantly beating the market at the current time, and stay with that fund so long as it is doing well Believing and trusting in any fund manager is a mistake. Sometimes they are hot, and sometimes not. Performance is all that matters. Paying a load or a redemption fee for a fund is just plain stupid. Some people say you should always have some money in bonds, and provide complex asset allocation models for you to follow.
Diversification is for wimps and weak minded idiots.
True, sometimes this is instructive. But consider Robert Sanborn, manager of the Oakmark Fund. Listen, dudes, I don't give a rat's ass about your investment methodology. I want to make money, and you are doing a bad job of that. So expect nothing from me.