There are a number of online systems that 'claim' to offer x% returns on winning computer generated picks of NFL or NBA. It's best to be wary of such systems as the betting odds are heavily skewed against you.
Sports arbitrage trading is a method similar to the stock markets where profits are made from the price difference in two markets - say cash market and futures market. The difference in price creates an immediate risk-free profit that is independent of the subsequent movement in price of the instruments traded.
A similar concept applied to sports betting works to 'reduce the risk of loss' to you (the bettor) and 'attempt' to maximize gains from a placed bet. The idea is to leverage opportunity risk in your favor and exploit known anomalies in the betting patterns. It is these very anomalies that help generate profits on sports picks - be it baseball, basketball, football or even horse racing.
One system you can look into is 'Sports Betting Champ' by Dr John Morrison. Dr Morrison is a sports statistician from Cornell University and a veteran of across-the-board sporting picks. Pre-season trends and other parameters (which he reveals in his course) help him zero in on possible game plays for the season and narrow down the opportunity window to specific profit plays.
Check it out for the videos of those who have used it and swear by it. It could very well give you the betting advantage that you're looking for.