Sports betting
What is a sports betting strategy?
A strategy is a written rule about which prices you take and how much goes on each one. If it changes because you feel good about a game, it was never a strategy.
Three parts: a way to find a price you think is wrong, a stake rule, and a record that catches you out when it stops working.
Finding a price worth taking
This is the hard part and there is no shortcut in it. Most workable approaches involve specialising narrowly, then comparing across books until one of them is slower than the others to move.
Specialising beats breadth every time. Somebody who watches one league obsessively and bets three markets in it has a chance. Somebody betting nine sports on a Saturday is buying entertainment, which is fine, but it is not a strategy.
Staking
Flat stakes, one unit, every time. Fractional Kelly if you can genuinely estimate probabilities, and almost nobody can.
What ruins accounts is not a bad opinion, it is the stake that goes up after a loss. Martingale-shaped thinking has bankrupted more bettors than any single wrong pick.
Keeping a record that hurts
Log the price you took, the stake, and the reason in six words. Not the result. Results are noisy and reasons are not.
After two hundred bets the log will tell you which of your reasons actually earn money. Nothing else will. Two hundred is roughly a season for a focused bettor, which is why patience is a strategy input rather than a personality trait.