I'd suggest doing the Ferguson Pre-flop Academy challenge. The concept there is to use standard raises for the playable
hands in each position, with a varying bet depending on position only (not the cards). Play the challenge several times. (To get through it, you have to make a ton of raise-or-fold plays -- which is also a huge thing to train yourself to do.)
Now, I don't love raising AA 2xBB in early position as required-- but what often happened was that another player would reraise you, and you can then make sure it gets heads up.
It's a good challenge to systematically play preflop in a way that hides the strength of your hands, and see how that affects both your results and the response of the other players.