You go with what works for you; those who watch almost every match in each season, some of them don't waste time in running research about previous matches again as they watch both team performance before either last season or just in a concluded match; they can make their prediction from there.
Some people are just like your friend; even after spending hours and days making your research on your game option, sometimes your prediction comes out wrong, while the next player who just spent a few minutes selecting random matches ends up winning. It's just all about luck sometimes, but the research just helps increase your chance of winning.
That's the reality of prediction no amount of research that can usher you the exact result because this betting is purely a game of luck to felt that research can give accurate results there would have been more wining than losses because the past record or research made would have been given people wining because it would have been like mathematics where one plus one is equal two, I over see betting as luck even if experience can help but can't exceed 25% to which luck operate.
Gambling and betting are basically a game of chance where random patterns will always be the main factor in it, but even so we can still minimise losses by doing research and analysis before the bets we make so far, although it cannot guarantee a 100% win but at least our chances of winning can be greater by making more rational decisions in the bets we make than if we bet blindly and just depend luck, victory in betting and gambling cannot be separated from luck, but I think analysis and expertise are also very important factors because luck will not always cover us.