You could practice using the streaks method, which involves shooting for streaks of questions answered correctly in a row.
For example, for a given topic, you could do easy questions until you get 15 correct in a row, then medium questions until you get 15 correct in a row, and then hard questions until you get 10 correct in a row.
Alternatively, you could do Quant questions from a mix of topics until you get 15 easy, 15 medium, and 10 hard questions correct in a row.
In the process of achieving such streaks, you'll develop skill in avoiding careless errors and getting Quant questions correct consistently.
This post covers in more detail how to use the streaks method.
How to Ace the GMAT Using the Streaks Method For some examples of people who used the streaks method to get good results, see the following posts.
Used the streaks method to achieve a 90-point increase to 755Used the streaks method to achieve a 100-point score increase in a few weeksMastered RC using the streaks methodMastered CR using the streaks method