Predictions are mostly shit. Its just luck.
I won .1BTC today in sports from 0.001btc. its all luck.
Gross oversimplification, sports betting can be profitable (+ev, in the long term) by finding value bets where the actual odds of events happening are better than the odds given by bookmaker, but as you might imagine this is rare, and so the slim <0.1% of all sports betters who are +ev, are usually using advanced systems, or betting fixed games, or finding some other oversight of bookmaker (I refer to traditional sports betting, not trading on exchanges). The topic creator mentioned tips for the upcoming world cup, which already tells me this won't be a +ev venture, the world cup is about as mainstream as you can get in sports betting.. and there will be no value bets. Look up vig to also realise why finding value bets are hard.