The most important aspect of successful sports betting is knowledge. Knowledge is unquestionably power, and also the more you've, the more bets you'll win. The key to winning bets is feeling confident with your betting decision. The best way to feel confident is to conduct a little research, learn about the teams, players and coaches, and then suggest your decision.
Once you have done some study, you will have concrete reasons as to why you are betting this way. This is much smarter than betting with your gut instinct. Your gut feeling might win that you simply bet here and there, but in the future, you will surely end up losing more bets than won by you.
The best way to know if you have done enough scientific studies are to explain your reasoning in making that particular bet. If the argument you're making for one team over another is weak and never backed up by much evidence, this is simply not a bet you should place. However, if your argument is powerful and persuasive, you ought to feel very confident in placing that bet. The greater bets you add when you are confident, the more bets you'll win.