Read up on John Bogle, the founder of Vanguard. He basically did a meta-analysis of how mutual funds performed over a long period of time, when actively managed by fund managers.

He found that none of them were able to outperform a simple index of the S&P 500. Which means even people who pick stocks for a living don't know shit. PLUS you're paying them management fees (some up-front, some hidden) for the privilege of their "expertise", even though they actually suck.

You're better off just spreading your money over everything with index funds, leaving it alone, and trusting that long-term growth will continue. You can't outsmart the market.