Hey Adsefghijk,
You need to be able to justify a 3bet with QQ vs MP open. Villain needs a wide range and a low Ft3bet. If either of these is not true, or you have no info, you should flat QQ vs EP open.
I would cbet the flop - depending on how wide villain calls he may have PPs, Jx, flush-draws. If you think value is thin, bet smaller.
I don't mind betting again on turn very small for value. Maybe $0.80 or so. Jx/FD's/PP may still call + you often buy yourself a showdown or make an easy fold vs a turn check-raise. Nothing too wrong with your line however.
On the river you still beat diamond draws, but with no reads that opponent is capable of bluffing I would just assume he is not at these stakes and fold.