Your car is to rights. *I have no idea what this means. The woman who came yesterday was on the right side of thirty. *I am not familiar with this idiom. When I googled it, it looks like the idiom is "wrong side of [age]" and can't be changed to "right side". You should set oneself right with your friends. *You should set yourself right with your friends. [advice] OR *One should set oneself right with one's friends. [general principle] My son is at the head of the class. *Great job!

Your car is on the right. The woman who came yesterday was on the right side of thirty. - correct One should set themselves right with their friends. My son is at the head of the class. - correct