Clean Up Your Act

CLEAN UP YOUR ACT means that someone needs to do much better, especially because they are behaving unacceptably.

For Example:

John’s been late for work almost every day this week, and he always stays out late with his friends. He needs to clean up his act, or he’ll lose his job.

The recent scandal yet again shows that voters will continue to lose confidence in the government until it makes a real effort to clean up its act.