see eye to eye- agree. Joan and Grant see eye to eye on spiders. They both hate them.
put one's foot in one's mouth- to say something embarrassing and then realize it was bad. I said Frank was ugly and then I realized he heard me. I really put my foot in my mouth.
stay on one's toes- be ready/ prepared for something. Firefighters have to stay on their toes. They may have to fight a fire at anytime.
keep an eye on- watch something to make sure it is okay. Could you keep an eye on the baby while I go to the store?
lend/give someone a hand- to help with something. That box looks heavy. Let me give you a hand.
be in over one's head- be in a situation that is very difficult. Alan was really in over his head when he started studying advanced chemistry. It was so hard for him.
keep one's fingers crossed- to hope that something good will happen. I'm keeping my fingers crossed that I will get that job.
get cold feet- get nervous, especially before marriage. The night before the wedding Alex got cold feet. He wondered if he should really get married.
have one's heart set on something- really want something. My son Tommy really has his heart set on that new bicycle. Maybe I will buy it for his birthday.