Summer races are planned, training is going well, you're working on starts and settles and sprints - but how much have you thought about your warm up? When I was much younger, I would worry that too strenuous a warm up might be detrimental to my race, and that I would tire myself out. As I get older (and wiser?), I find I need a much longer warm up than in those younger years.
Science will tell you that as you get older, it takes longer to warm up the aerobic system for peak efficiency, but it became pretty obvious to me when I'd do pieces on the erg and my first piece was never my fastest, despite feeling that I had done a solid warm up and was ready to go. My 2nd, 3rd or sometimes even my 4th piece (if they were fairly short) would be my best, but never my first.
As you continue with your training, pay attention to what and how much you're doing on your warm up. If you're ever pressed for time and shorten your warm up, does your workout suffer? Which piece in your workout is generally your best? I have a much easier time warming up for a head race, doing plenty of steady state and some longer anaerobic threshold type work, but for a sprint race, you'll need to throw in some starts, 10's, and even 20's - it's up to you to figure out how much is enough. Play around with all of this during your everyday training and find out what combination of work best prepares you to race.
As for drills in a warm up, I'm not much of a drill person but the one I find I turn to most is simply half slide rowing. It tends to sharpen my catches, as I'm not trying to overreach, it makes me focus on getting my body angle fully established by half slide, and, for whatever reason, it helps clean up my finishes. This might not be the drill for you but if there is a certain drill that makes you row faster, cleaner, longer, by all means add it in.
Experiment to find out what warm up works best for you so you can be prepared to race your best.