。
I made an effort to get good grades.
Literal
Good grades [object-を] get-volitional [quotative-と] effort [object-を] did.
~と努力をする ('make an effort to X') uses と for the quotative content of the effort — 'put in effort toward the goal of doing X.' 取ろう is the volitional form of 取る ('to take/get'). 努力 ('effort') + をする verb phrase.