I try to center myself. For example, I focus fully on breath for a few breaths, think 'I am breathing in, I am breathing out'. Focus on how your feet/bum/spine

I try to center myself. For example, I focus fully on breath for a few breaths, think 'I am breathing in, I am breathing out'. Focus on how your feet/bum/spine are supporting your weight, readjust slightly if your posture is awful. Get whatever problem you're working on out of your head. After a few seconds of this, I come back to the problem and usually am able to do at least slightly better. It's like power cycling your brain after it gets stuck.