Hi,
Although I am not an expert on the matter, but I suggest you to subscribe to
GMATCLUB tests to improve your quant score.
These tests provide you with difficult questions and help you analyse your weak areas. Also the total number of quant test is 25+ so you get lot of practice questions.
About verbal, which is seems difficult to improve but is actually just like quant section where the actual test is of the logical ability and not the grammer rules,
Try to make notes and revise from those notes often because retention of rules and question wise respective approach is key factor to ace Verbal section.
All The Best.