heres a good tip from a guy-me-who has good arms.
randomly pump them up when possible, do couple pump sets even on legs day,i do that.
if youre affraid of "overtraining" them, well, go and try to actually train them so often and hard, so they become overtrained.youll find out,they can take quite some abuse.
in plain layman english terms, dont be a pussy, train the hel out of them.
instead of waiting at home for that next 3 hr frequency meal thatll only make you fatter and faster on the way to permabulk city, go and train something.
This ^, train the shit out of your weak points maintain the strong points = symmetry.