Metro C,
I ride in C and welcome advice. Having ridden in D grade for over a year the only advice I got once was in a combined C/D grade when I rode up the inside and got yelled at by someone.
I also get particulary nervous when the pace slows and the group rides 4 or more abreast, there are bikes all over the place.
I also find myself sprinting then coasting then braking a lot on Friday nights.
What sort of advice have you got?