The clue is in the title. Keep it simple by looking out of the window as much as you can. This is the best thing for keeping your SA high. With the mental arithmetic, practice, practice, practice. Get used to manipulating the 1:60 rule for headwind & tailwind.
Work through as many problems as you can on the ground, go through as many 'what if's' at the planning stage, such as diversions, weather re-routing, high ground etc and it will free up some capacity in the air.
Good luck!
