I have many "routines." Here's one: If I'm not on a project, one thing I will do is wake up, select a minute or two of random music (today's was Janacek's Sinfonietta: II) on my ipod, and listen to it over and over for an hour during cardio at the gym. Then after I get back, I'll attempt to notate it from memory. I don't have absolute/perfect pitch, so I allow myself a starting note, but I try not to use the piano for guidance as much as is possible. I'll usually spend an hour-and-a-half to two hours on this, and then check it against the actual score. Because of anomalies in recordings, I don't think it's possible to ever truly get 100%, but the closer the better. This has many advantages: ear training, orchestration, familiarity with the lexicon, penmanship, speed, and discovery of my own ear's biases (the way I "mishear" things in my own mind). I do this in pencil, and watch myself make the corrections on my score to match the original. Then I usually do an hour or two of speed sightreading exercises to keep sharp - all clefs, transpositions, so I can think in real-time no matter what instrument I'm dealing with. Then usually I pick a movie to watch, and turn off the sound, but turn on the subtitles. I make a cue sheet for it, guessing what the entrances/exits will be, and notations for my first instincts as to the drama. Then I watch it down again with sound to compare. No matter which director's work you're talking about, Western films have alarmingly predictable edit structure, and this helps me hone my sense for overall flow and presence of music, by-and-large. After that, it's usually a few hours of just free-form writing, but one thing I always do is finish whatever I start. Sometimes it's just a simple quartet piece, or a reworking of a familiar song (on the 4th of July, I did a thing around our national anthem, for example). Between that stuff, shower and meals, etc., it's usually an 17-20 hour day, and then I do a different set of things the next day.
The training isn't really in the method - it's in the approach. I look for weaknesses and work them. I have many weaknesses :)
_Mike