Get above yourself
Definition 1 of 1
Pro Tip 1/3Colloquial Use
Used more in casual talk among friends or family, not in professional settings. 
Tom, don't get above yourself just because you won the game.
Pro Tip 2/3Negative Connotation
This phrase is a criticism; it means someone is arrogant or has an inflated ego. 
She's starting to get above herself, ignoring everyone's advice.
Pro Tip 3/3Humility Reminder
It's a way to tell someone to remain humble and not overestimate their importance. 
You did well, but don't get above yourself - you still have much to learn.