Very good critical observations on your own driving...best way to get to improve on your riding!
Ya just have to relax and focus, at least I do when I find myself tensing up and grabbing the grips too much. I think everyone does it from time to time. Some days I may leave the house and ride so smoothly you'd think I was a pro (joke!!!) and other days you'd swear I couldn't control the bike if my life depended on it. When you find yourself tensing up going around a corner and grabbing the handlebar too much you can pull in and relax or if slowing down and telling yourself to focus helps then do it!