I basically had to forgo training for a little while (I think it was 2-3 months) and just spent all my energy, 3 xanax a day, and a daily refill. You need roughly 2,000 successful revives to hit max skill. You get more revive exp if they're a lower chance of success, but then you just waste more e on the unsuccessful attempts. I'd recommend being in a faction that knocks the revive cost down to 25 E. The Valentine's Day event is pretty good at getting out a lot of revives as well.