Backtest. Most traders lose mainly because they think they have an edge but they don't. You read these books and all this stuff online telling you "this is a high probability setup" but do you know that for a fact? There's different ways to backtest, but I think the best way for a beginner is manual backtesting with a chart and an excel sheet. This builds up that screen time and pattern recognition faster. This video shows how to do that. Once I saw someone do it, it didn't seem so boring and awful as I thought it was.