The first thing that you need to understand is how to control yourself on bad situations, and you need to learn how to be prepared if there is another crash or something related to that, because it is not something easy to handle after all
Indeed, discipline first. Emotions is your worst enemy in trading. When you see a coin or token that is currently pumping, don't get excited and buy thinking that sudden surge of price will continue because you might be too late buy. Use tools like RSI and Bollinger Bands to help you decide if the trend will continue or not.