in someone's good books
in (one's) good books
Regarded favorably by one; thought of kindly or approvingly by one. Maria has been in my good books ever since she stayed late to help me finish that project. If you want to get in the teacher's good books, try to participate more in class.
in someone's good booksBRITISH, INFORMAL
If you are in someone's good books, you have done something that has pleased them. I never really was that bothered about being in the teacher's good books. While Becky was out, Jamie made an attempt to get back in her good books by doing all the housework.