Systematically tracking betting results with full transparency — by league, bet type, team, direction, and time period — and using that data to honestly assess whether you're winning through skill or luck.
You track every bet publicly or at least honestly. You separate results by league and competition. You track bets AGAINST teams as well as bets ON teams. You distinguish between units won/lost and actual money (accounting for vig). You don't count leans or unofficial picks in your record. You don't cook the books when a line moves.
Tracking bets AGAINST specific teams revealed that "against Manchester City was the most profitable PL pattern." The asymmetry of who you're fading matters as much as who you're backing — some teams are systematically overrated by the market, making every bet against them +EV regardless of who they're playing.