Watching other boats is especially helpful for figuring out which angle is best to sail downwind. Watch your performance compared to nearby boats.
Are you sailing higher or lower than them?
How is your speed through the water?
Which boat is making the best VMG to leeward?
Sail a little higher or lower to see if this improves your VMG relative to the other boats.
While you are going fast, try to remember how the boat and sails look and feel.
NOTE - On this slide the angle of 22 degrees has been inserted. Remember this for later.