The most important thing you need to understand in trading...
As a professional trader whose income depends on trading I pay great attention to risk management. The objective is to make lot of money without losing money. Which essentially means avoiding certain market periods and proactively going in to cash or short and same way to get in t new trend at right time.
To do this I use a risk management tool based on market breadth called Market Monitor. The Market monitor turned negative 9 trading session ago and we closed all long positions.
For swing traders and position traders a market timing filter is very important. You should have some filter to tell you when is the right time to be in market on long side. When should you be in cash or short. And when should you climb back in to market. Absent that you will go through cycle of gains and losses.
If you want to stop that cycle then study market timing tools. There are large number of tools which tell you when to be aggressive and when to be on sideline.