Something to add to this (from this image from Matt Costa), when you pump into waves, you must make sure to put the most effort into pumping at the peak of each wave, where there is maximum lift. You need to glide down the back of each wave.
I noticed I was doing this, but didn’t really realise what was going on until looking at this image. Watch someone good pumping out, and you’ll see they sometimes double pump, to get the peak of two bumps close together, and then otherwise do a steady pump to time their pumps with the peaks.
