After the third year of high school, don't do too many questions, summarize the methods of doing them, and make clear the questions and mistakes, so that you can hope to get high marks in the college entrance examination. Never give up any problem, even the most difficult ending.
Carelessness is a very serious problem, and many people can't change it even if they take the college entrance examination because they usually muddle along. I suggest you get into the habit of slowing down the speed of doing the questions and make sure you do them correctly. This should start as soon as possible. In the third year of senior high school, if you can examine the question carefully and tell yourself what you need to pay attention to when doing this problem, you will be very close to your goal. It's equally important to have a check-up after you finish the questions. You should be able to check the numbers. If you think something is wrong, you must do it again. You can't miss the same type of topic once and make mistakes twice.