Flying from high to low (pressure) or Hot to Cold - Look out below. (Mostly for IFR, but still good to remember)
Here is an old one from my recip days..Fuel consumption of an aircraft engine is equal to 1/2 the Hp divided by 10. (160 hp engine. 1/2 the hp = 80 diveded by 10 = 8 gph)
If another aircraft appears stationary in your windscreen and is growing in size....alter your course.
I got my PNR's as well..but to lazy to type them up