RudimentsLearn all of these at at least platinum speed.
As a tenor drummer, my mantra is that we are snare drummers that have to play all the snares stuff on different drums. We need to be able to play whatever the snare can play, and then divide it up between a set of 4-6 drums depending on what set you use. I don't know how good this guy is you're trying to keep up with, but if he's any good I'm sure he knows his rudiments quite well so to learn these would be the first step in keeping up with him.
Second, you need to make a practice scheduel and keep up with it every day. When I marched corps, this had to be done NO MATTER WHAT, no excuses. Here's what my scheduel looked like.
Exercise - Tempo - Duration - Time to practice
Eights - 100 bpm, 130, 160, 190, as fast as possible - 6 times each tempo w/ last 2 times each cresc. then decrec. - 6 min
Bucks - 100 bpm, 130, as fast as possible - 4 times - 6 min
Accent tap, both hands, triple, duple - 120, 140, 160 - 4 times - 7 min
Flams - 100, 120 - 4 times - 1 min
Double, tripple beat - 120, 140, 160 - 6 times - 8 min
Singles - 140 - 4 times - 1 min
Stick Control - 100, 130, 160, as fast as possible - 4 times each, all dynamics - 2 min
Triplet Diddle - 110, 140, 160 - 6 times each - 5 min
Paradiddles - 80, 100, 120 - 4 times each, 4.5 min
Triplet rolls - 120, 140, 170 - 6 times each, crec. and decrec. - 5 min
Duple rolls - 110, 120, 140 - 6 times each, crec. and decrec. - 5 min
Hybrid-Rudiments - any temp you need to work on - Learn at least one new rudiment at a new speed - 5 min
APPLICATION! - Now you actually practice the music you need and work on whatever you are having problems on. - At least half an hour, hopefully an hour.
Well thats it! If you follow that guy, you will be really, really good in a fairly short period of time (it took me 3 months of that every day to be able to play a full SCV cadence and be the Tenor section leader as a freshman.) It's a lot of work, but when you look back and see how far you came, it will be worth it!!!