The most common mistake with sports investors is money management. Money management ensures that your bankroll can withstand a bad day or week. This can happen to anyone, and if they tell you different they are full of it.
It is similar to a diversified portfolio. The problem with most novice bettors is that they will invest the majority of their money (25% or greater) on one game, on any given day or night. If they lose they will usually chase by doubling up their investment and even going "all in". This is something that you NEVER want to do in your goal at being a winning sports investor. Ideally, a bettor never wants to have OVER 5% of their investment bankroll committed on one game. This ensures your investment gets a large enough sample size where you will see correlated results using a great handicapper like you find at TripleCommaPicks.com.
Investments here are found on one scale, the most accurate scale for a winning sports investor, with @TripleComma, all plays are between 1u*(Unit) to 5u*(Units). This would mean that a minimum investment would be 1u*, meaning an "average" investment on any given event. In turn, a 5u* bet would be a MAX investment, meaning your largest investment on any given event. Online you will often see people with huge unit scales, anyone who uses a scale of 50u* to 100u* is just unrealistic.