A good tip I was shown (after 20 years of flying) : A persons finger on a WAC chart covers near enough to 10 nm. Try it. 2 fingers 20nm 4 fingers 40nm etc You'll quickly work out for your own hand where it has to cross the track drawn on the chart to be surprisingly accurate.Very handy on a rough day bouncing around with no auto pilot.Wish I had been shown this for my pre GPS days. I still use for identifying items of interest that we see out the window from time to time.
Cheers RA