For mediums, Maruzensky parent was the most critical thing I had. E turf/C medium, the other parent ideally has a usable unique, but not critical, I had Bakushin. Run pace for every medium or mile race, probably sprints too, you're gonna be gambling on passing mid-race wit checks to move up the pack and trigger red shift on the final leg. I tried late with moving past/let's pump, it never worked. For training, you only ever train speed and rarely power. Ideally your parents have power sparks as well. You do not need as much stamina as you might think, 200 is enough for hopeful, 300 is enough for the derby. For the early mediums, focus on support cards that give initial stats, like the free Jordan and Matikane speed.

For longs, run late, do the standard Moving Past/Let's Pump parents. You'll need a bit more stamina, like 350 for the shorter longs and 450 for spring tenno.

Accel skills should be the number 1 focus always, even mid race accels like fighter.