There are plenty of betting strategies, guided by which authors make their sports bets. These betting strategies are very easy to find in Internet to study and start using in sports betting.
Each gaming system has its positive and negative sides. If positive side of betting strategy is an ability quickly to multiply your bankroll, negative side of this betting system is a high risk of losing betting bankroll.
Conversely, if positive side is reliability of betting strategy, for which it's very difficult to lose money, negative side is low profitability.
Ideal betting strategy don't exist, what may bring a regular income and be suitable for all players. Each bettor has own betting style: someone likes to seek out sensation, somebody is looking for 100% reliable stake. It's important always to remember that every betting strategy can result losing bankroll! And every bettor would always remember it!
Naturally betting randomness is a direct path to loss, so you need to use some betting strategy to make a profit from sports betting. But don't follow strictly betting strategy in order don't lose money, especially for sports betting strategy based on Martingale betting strategy.
So, Seventeenth bettor's mistake: strict use of sports betting strategy.