I found out today that I was significantly less anxious during my LR sections because I decided beforehand that I would check the time after the 10th question, the 15th, and at 20. Obviously if I felt I spent a long time on a section I might check how much time has passed by, but I feel like constantly looking back and forth between my watch and the questions ruined my train of thought on many occasions. I had to turn my watch over so I wouldn't be tempted to keep looking.
For reading comp though, I'm not sure when to be checking my time. It would be ideal to only check after each passage, but I don't want to lose track of time after spending a good deal of time on a tough passage or question. I'd love to hear what top scorers have put into habit.