Opinion Doesn’t Count
In most other fields of activity we need to convince people around us that our opinion is correct. In the market, it just doesn't work that way. It's suicide to try to trade from your opinion. Instead of insisting that you are right, you have to get rid of your ego and any opinion you have of the market. What you want, is simply to be in tune with what's happening at the moment. Connect to the reality of what you see.
If a move goes against you, then you have two choices as to how you can think. Your first choice is that you are convinced you are right, and the market is wrong. If you think you know better, you can hold your position, and hope prices eventually move your way. Your second choice is the realization that the market is never wrong.
If the market goes against your position, then you are wrong and have to get out. Taking the first choice is the road to the disaster in the market. The second choice is the choice taken by successful traders. It's not easy to regulate your mindset to think in this way, but you must force yourself to do it until it becomes your usual way of thinking.