If you want to win...or at least not lose in sports betting then there are a few things you need to know and some things you need to not do. These are my opinions but after seeing thousands of guys bet different, the ones that are successful do the same things.
1. Treat this like a business...Don't bet on a game just to have action. Only bet on games you feel good about.
2. Don't ever play a parlay or teaser. These are in the books favor...you can win a few of these but overtime the payout is negative.
3. Bet around the same amount on each play. Sure you can throw a little more now and then but generally you should play all the games for about the same amount.
4. A good rule of thumb is if you like the favorite or over then play it early in the week and if you like the dog or under, wait til right before game time to place the bet.
5. Take advantage of books like pinnacle who give you +juice like +105. Heck placing those bets it is like you are the bookie.
6. Don't buy any points. You will be tempted to do it a lot. You see 7.5 and buy down to 7 or 2.5 and buy to 3...It may save you from time to time but I am telling you overtime this will crush you.
7. Know where the action is. This doesn't mean you cant play public plays but try to avoid them as much as possible.

There are more but these were some off the top of my head...More to come later