If you are on a home team that's anywhere from a PK to -3 in football, you're probably on a loser.
Today was a prime example in the NFL. Chiefs? Lost SU. Falcons? Lost SU. Browns? Lost SU. Jets? Lost SU. Only the Bears managed to win as a home fave in the FG or less range.
Same rule seems to apply for basketball. I don't know how many times I've looked at a home team at PK or -1 and thought, "man, that looks like a great play" only to watch it crash and burn.
Road dogs of +3 or less. Home dogs up to +6.5 (or just home dogs altogether if you'd like). There is no "magic bullet" in gambling, but you'd be comfortably in the black if you just focused on fading home squads who are barely favored and/or road faves in general.