head over heels	completely in love
have/keep a clear ˈhead	be able to think clearly
have half a mind to do something	used to say that you would like to do something but you probably will not do it
rack your brains	to think carefully about something
set mind on	To be resolutely or inflexibly determined to do or acquire something.
make up your mind	to decide
keep your head above water	to just be able to manage, especially when you have financial difficulties
speak your mind	to say what you think about something very directly
give head	To allow one to do what one wants
be in two minds	to be unable to decide about something
have sth on the brain	to not be able to stop thinking or talking about one particular thing
out of your mind	unable to behave or deal with things normally because something has made you very worried, unhappy,
turn sb's head	it has an influence on how that person behaves, especially by making them too proud:
pick sb's brains	to ask someone who knows a lot about a subject for information or their opinion