If you're going to stock pick, then you have to take a page out of Ted Wiliams' playbook and 'wait for your pitch'. Williams was the last batter in MBL history to hit over .400 for the entire season, finishing 1941 season at .406.
That's what stock picking is. Have your money in cash, or a cash-like instrument that won't go down in value and wait. And wait. and wait. Then, when the pitch that you've been looking for comes, go all-in.
You've got to look and find that hidden gem, the one that everyone else, aka 'the market', is overlooking. You've got to see something that the market doesn't see, something that is hiding in plain sight. To do this, you need an edge, some sort of special knowledge that most people are unaware of or routinely discount.
Most people can't do this because:
1) It takes discipline. In an undisciplined world of instant gratification, waiting is really hard.
2) It takes analysis. Most people have no idea how to analyze anything, much less a company & the underlying stock.
3) It takes an exit strategy. You have to know when there is nothing left in the stock and it's time to move on.
These traits can be practiced and results improved, but, the learning curve can be steep. Thus, I generally recommend indexing to anyone who asks.