If there are hills on the route, ease up instead of going as hard as you can. In general, don't burn your matches too soon, so no surging on the flats and especially not downhill (least efficient use of your energy).
Also remember to hydrate and fuel; at that avg speed and those distances you can't (yet) ride on stored glycogen alone.
For training outside those group rides, really any kind of structured riding (not aimless tempo) would be beneficial, as long as you adequately rest and recover as well to get the most benefit out of that training. No need to overthink that part.