Paul Steeles book is the one to get for football bets, he analyses the various systems that are possible as well as suggesting one of his own, some are simple based on form or table position and can be worked out in seconds, others are more complex with weighting systems etc and need many hours of research and data analysis.
His power system does well (as to a point you would expect) but some of the simple ones are pretty profitable as well.
Amazon link to the book