This is honestly the most important question I've seen on here. Psychology separates the profitable bettors from the ones who lose everything. The fact that you're aware of this problem already puts you ahead of most people. Create a written set of rules for yourself and follow them religiously, no exceptions. Never place a bet when you're excited, angry, or feeling desperate to recover losses. Successful bettors treat each wager as part of a long-term plan, not as individual events where they need to win immediately. Track your emotional state when placing bets too, so you can see if there's a correlation between how you felt and whether the bet won or lost.