They do not have to be following the league or games to be able to choose the teams that will win. There are websites and mobile applications that can tell you which clubs are in form to give you a victory or clubs that have been playing very well then you do your analysis, you can see which club is going to be the best option to go for to increase your chances of winning. I would not bet on a game without knowing everything about the two clubs playing and I do not understand how people just use only guesses to play their games. I know it works for them sometimes but I think most times they will lose because betting is not that easy especially for sports games that you need to know the strength and weakness of the clubs playing.