Measuring distances
Best rule of "thumb" I ever learnt for map reading - even used it for flight planning.
Your thumb, at the widest spot, is approx 11nm on a WAC and 3nm on a VTC.
Wanna measure a distance, get the thumb out. For anything you're likely to need inflight - it's a good enough approxmiation and saves you needing to stuff around with rulers.
Also, DONT look out the window for every feature. For a leg of say 20 minutes, do a gross error check at the start, maybe look for one town/city/mountain in the 1st 10 minutes, do your 1 in 60 and then wait til your revised arrival time.
As soon as you start feature-hopping you'll find it very hard not to turn back towards what you think your track should be - don't! If you know you're off track it's not a big deal as long as you maintain heading until the 1/2 way point, work out the drift, double it and turn back towards it (i.e. do a 1-in-60).
If you feature hop and change track continually then you've got no hope of figuring out what the actual winds and hence drift angle should be and no hope of arriving over your next turning point.
UTR