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.