Keep body and soul together
If someone is able to keep body and soul together, they manage to survive.
Example: He was unemployed and homeless, but he somehow managed to keep body and soul together
Keep your fingers crossed
If you keep your fingers crossed, you hope that something will be successful.
Example: I’m doing my driving test tomorrow. Keep your fingers crossed for me
Keep someone posted
If a person asks you to keep them posted, they want you to keep them informed about a situation
Example: Our agent promised to keep us posted on developments in the negotiations
Knock (some) sense into somebody
When you knock sense into somebody, you use strong words or methods in order to get that person to stop behaving stupidly
Example: When Jason announced that he was going to drop out of college, his father managed to knock some sense into him
Know which way the wind blows
This expression means that it is advisable to know how a situation is developing in order to be prepared for the changes that are likely to happen.
Example: Before we decide on anything, we need to know which way the wind is blowing