I've been investing nearly 20 years with my own $, and nearly a decade with others' $.
The small investor makes money by the power of compounding, investing wisely in a diversified portfolio of quality investments over time, and being patient.
If you have the time and aptitude to dig in deep and find your own investments and not let fear, greed, and ego get in the way, perhaps you can learn to do your own. If you don't have the time, aptitude, and emotional makeup to do this, you're better off investing with a professional.
When picking your own individual investments, it's all about being forward-looking. Since no one can predict the future, you'd better really learn to know what the hell you're doing and not think you're so smart that you're never going to be wrong. Because you will be wrong sometimes. Diversify and learn to manage risk.
If you do it long enough the right way, you'll turn a few bucks into many over time. But you won't beat the market EVERY year, no matter how good you are. Nor will you never have a losing year if you do it long enough. You won't average 50% or more a year if you do it very long, and it's highly unlikely you'll make triple digits in any given year. Not even the very best average mid double digits over time.
And good luck if you decide to "day trade" - most figured out 15 or more years ago that it's too risky and too expensive. Even if you can trade for as little as $2 a trade on average, you do 3 trades a day for a year, you've spent a good $1500. Not a big deal if you have 6 or 7 figures to invest, but if you've only got $30k, that's 5% right off the top. And those big funds like DE Shaw and Jim Simons' fund Renaissance that use those automated HF trading systems these days will probably eat you alive pretty quickly.
Go to 2:40 here and listen to what the fund manager says about human traders:
I'm skeptical about his track record though. He'd need to show me proof that he's never had a losing month before I'd give him any $.
If you wisely choose to invest with a professional or to spread your $ among several money managers (or both), them having a track record of success is very important. Preferably a long track record. Would you listen to some "guru" on a BB forum regurgitating info from some 1990's day trading books & seminars who cannot provide you a track record of success going back decades or even a few years? Or would you rather read up on and and listen to Soros, Icahn, Buffett, Lynch, Berkowitz, Yactman, Bruce, Paulson, Einhorn, et al?