You need to learn your lessons and mistakes. By doing that, you can then improve your skills and not make the same mistake. Hence, you have to go through your trading history, identify trades which did well and poorly, analyse the issue and not repeat the problems.
One approach is to screen capture your trades after end of each trading day. By doing so, it acts as a trading diary for you to look at and go through when things are not going your way. In fact, you should go through on a weekly basis. To do a thorough job, you should screenshot your trades and write about it in a trading journal. Of course, you will need to indicate the reasons you take the trades and your post trading thoughts. This approach should constantly remind you what to avoid to improve your trading results.
The above approach can be quite tedious especially if you are a short term trader and you take many trades in a single day. However, you can take a small short cut by just recording trades which you lost money. By consistently doing so and reviewing it on a weekly basis, i am sure your trading results can improve in no time.
Give it a try and tell me how it works for you.