If you want to win and don't mind working on props
Lookt for two things:
1. Unique props. If only one book has it, the line is not as sharp
2. Matcup props, especially versus non-NFL things. Tiger Woods, Daytona, NHL and NBA are common. In a matchup prop, there are twice as many ways for them to screw up.
Seriously, spend a few hours looking at these matchup props. It is worth the extra effort.
I love betting props and it is extremely profitable. But you have to spend twice the amount of work to find a good prop and then handicap it... Golf matchups are the easiest though...