Street Kombat......or Mortal Fighter.....Or something.....

Are you looking to simulate the experience that playing a fighting game provides, but in RPG format, or are you trying to write a fighting-oriented game that has similar styling to fighting games? The latter might be difficult, since the styles behind, say, Guilty Gear, Smash Brothers, Soul Calibur, Mortal Kombat, and Virtua Fighter are all pretty varied.

If you're trying to simulate the fighting game experience I actually wouldn't worry too much about mechanics for things like mental state and prior training. I normally really like it when games include those in factors for combat, but since without them it makes combat feel like it's just a bunch of soulless puppets wailing at each other. That's exactly what fighting games are, though. I'd focus more on analogs for hit-boxes, start-up times, frame advantage, mix-up, chip damage, super-bars, and so on.

Do you have experience in the tournament scene for any fighting games? It's not worth it to train up to tournament-level in a game if you aren't there already, but just being around people who are and listening to strategy they talk about could probably be a really great inspiration for you.

Also, I think a card game system did something like this at one point. UFS had some pretty interesting mechanics. I never got too into it, but that was mostly just because it was hard to find friends to play with.