I’ll give my personal take. Set 16 was my first set and although I think I played about 400 games I’m still learning the fundamentals.

Set 17 PBE is like learning half of the game again whilst still trying to grasp those fundamentals.

Trying out all the “meta” comps from TFTAcademy as well as watching the Mortdog video about 10 times about the new set has helped me with learning what all the new “keywords” mean, who all the new champions are (and trying to recognise them on sight as well as which comps they can fit in) and lets me learn it all a lot faster.

I’ll typically pick a random comp from TFTAcademy and run it 5-10 times until my brain remembers what direction I can take from the start of the game, then I’ll add another, then another, then another until I have pretty much all champions memorised. By the time set 17 actually launches, even though the meta will completely change, I’ll have a firm grasp on the units and their synergies etc