I believe the biggest mistake gamblers make is they put too much stock into win/loss percentages. They simply don't matter because every play - at least in my case and for any handicapper who is worth a grain of salt - is rated for money-management purposes.
I use a weighted scale - ranging from 10 dimes to 100 dimes - to rate my releases.
This rating system not only defines my success in terms of net profit at the end of the day, week, month or season, but it also gives you an idea of how strong each release is and how you should play it.
Two simple things to remember:
1) In terms of ratings, clearly a 50 dime play is twice as strong
as a 25 dime play; five times stronger than a 10 dime release.
2) Base the size of your wagers on the percentage of your total
bankroll for a given day.
To explain that second rule a bit further, let's say you've got $100 to play with on a Monday night and I've got a 40 dime play on the football game's side plus a 10 dime release on the game's total. That's 50 dimes of action on the table versus $100 to invest. That means you've got $2 per dime to play ($100 divided by 50 dimes). So, you would wager $80 on my side selection and $20 on the total.
The biggest advantage to this easy concept: You never get in over your head by betting more than you have in your pocket.