A lot of it I learned by osmosis, I think. I was terrible and piano and violin, but I can sing fairly well and I played trumpet for eight years before I was rejected for the school of music in college by the late Fred Mills himself. (I think of that episode as one of the last instances of misogyny in the brass world. My instructor when I was a teenager was certain I was going to be the next Wynton Marsalis, but girls still didn't "play trumpet" just fifteen years ago. Things changed for the better once the millennium ticked over and the brass departments at most music schools have loosened up a lot.)
Back on topic, composing for video games has gotten much easier over the years. Sakimoto had to program his own **** orchestral engine to get FF Tactics to sound the way he and Masaharu Iwata wanted it to sound. Now a composer has the luxury of using MP3s of live bands and orchestras for tracks, or at least using engines that can approximate orchestras with great accuracy, instead of being stuck with engines that can only do chip tunes.