Hopefully the "real coaches" will chime in, but here are some thoughts from a "coachee" rather than a coach. (Quick background, my Masters racing schedule in NJ is probably 2/3rds crits, not by my choice, but that's what they run...) The difficulty is that while crits would appear to be an almost "unique" class of races, the overall conditioning requirements are the same as any form of road racing. You do need the long base miles to support the specialized training which comes closer to, and during, race season. You still need to maximize sustainable power, even though in the crit itself, you aren't "on power" too long before you set up for the next turn. (The max sustainable power works as the "reserve" you're using up with all the small accelerations. The more you have in the tank, the more you have left for the crucial last few laps.) So the key workouts look virtually the same, whether you're doing a 50-mile circuit race or a 1-hour crit. For sustainable power, something like the classic 2x20min LT intervals. For VO2max, something like 4x3min max-effort/high-cadence intervals (work/recovery 1:1). The most "crit-like" workout I know consists of sets of 4x30sec VO2 intervals - while the 30sec of work seems short, you don't get enough time in the 30sec recovery to really recover, so by the 4th work interval of the set you're (at least I'm) really gasping for air - that workout is closest to crit riding. (I've never done more than 2 sets in one workout). Of course (and I apologize for stating the obvious) the best crit training is to find an early-season mid-week crit training series, and ride those.