Any soccer/football fans will tell you that it's a tough sport to predict for a variety of reasons: low scoring games, lots of potential for human error in officiating, high levels of competence of even weak teams, team dynamic vs individual skill, etc. I'd guess that it's one of the harder sports to build a prediction model for. Good luck!
But in many ways it is actually a sport that can be modelled fairly accurately. The betting markets have remarkable consistency, in that they 'agree' on what the odds should be for any particular match. Compare this with horse racing, where the odds on any horse vary wildly before the start. For example, a horse might be 10/1 in the morning, 3/1 half an hour before the race and 6/1 at the off. Whereas the odds on a football team will stay fairly constant.
So the matches may be difficult to predict the winner but the markets price up all non-random factors very well.