Mostly running at least a couple miles every other day, as well as sticking to a weightlifting routine I've had for years. Also began incorporating calisthenics and super setting pushups and other exercises we will see at OCS to help get muscle memory. Once your body is familiar enough with a motion your ability to do them gets way easier.
I'm not good at cardio/running but from a strength standpoint, I used this technique for lifting weights. Take an exercise like squats, versus assisted leg presses. You can push heavier weight on a leg press than you can doing squats, even with the ~70% incline force value (if you know you know?), so if you use squats to get your body motion right then you can use leg presses to help strength train without peripheral muscles needing to help with balance/stability/etc..
Translating that to pushups, using a bench press, incline press, dumbells, tricep/back exercises, etc. or other weight machines can improve your strength while actually doing the pushups gets your body used to that form of exercise.
Long story short, strength and repetition/practice play an equal part in the PFT exercises. I know I may be preaching to the choir for some/a lot of you, but ya never know who it could help?♂️
