Another good tip is to
STOP USING FR
GGIN' CALCULATORS IN FLIGHT!
It takes your attention away from the aircraft attitude while you concentrate on using tiny buttons and a miniscule display.
My students soon learn if a calculator comes out in flight it soon ends up in the baggage area behind the back seat.
The more you practise "mental gymnastics" the easier it gets.
Learn to use your whiz wheel (not just for time vs distance/fuel, but for multiplication and division as well). The dude who invented this thing was a certifiable genius!
Round numbers to make rough calcultions easier,
Eg. 4 miles off in 38 would be pretty close to 4:40, hence 6:60 or 6 degrees.
For cross and headwinds, I used
30 deg = 1/2 wind strength is x/wind
45 deg = 3/4 and
60 deg = 90%
Reverse the order for head/tail winds
30 deg = 90% head/tail wind
45 deg = 3/4 and
60 deg = 1/2.
At 60kts, 1 kt x/w = 1 deg drift
At 120 kts = 1/2 deg drift.