I struggle with it too. I have ADHD, so the whole idea of playing chess goes against everything that my mind and body want to do.
Couple of ideas:
1. Sit on your hands.
2. Make a checklist of things your are going to look at each and every move. THEN DO IT (I suck at the second part)
3. Even if you know an opening, and know the response, play it slow enough to remember why your playing it. I think there is a rhythm to playing chess. Keep it nice and steady.
4. Ignore how fast your opponent moves. Maintain your rhythym.
Hey guys. I recently had a game where I had a clearly winning position and was trying to convert it into a victory. I found that I was moving too quickly and not thinking about the position, and I actually took myself away from the screen for a second and committed to slowing down and actually thinking. The problem is that it never happened. I immediately made a silly move and lost the game. I have trouble gettng myself to think deeply about chess for longer periods of time. I often just move abruplty and don't bother to look at the consequences. I use 30|0 time controls, but I only use most of my time if the position is confusing. I still usually don't find the right move in those situations, but I want to know how to develop patience in chess in order to improve my game. I thank all of you who answer.