Super awesome in depth video about how to improve your hydrofoil pumping technique. We recommend to watch the whole video. You'll take a lot away from it.
I found the most valuable thing I learned on any foil is getting the wing into the pump zone. The closer the wing is to the surface, the less drag it has and the more efficient you are. There is a sweet spot that is just under the surface where you can put out a lot less effort and get a lot more glide. The water has weight that grows exponentially as you go down in the water column which makes sense when you feel how much drag the foil has when it is too low.
Enjoy and keep practising. Keep in mind that you can always grab a cheap training spot on Thursday & Friday Foiling Class, allowing you to tow behind the boat and find your sweet pumping spot.