spread yourself thin
To try to do too many things at once, so you can't do any of them well.
She joined four clubs and now she's spreading herself too thin.
Spread yourself thin means trying to do too many things at once. Use it with a reflexive pronoun: myself, yourself, herself.
Your turn
What's one thing you could stop doing so you don't spread yourself thin?
What's one thing you could stop doing so you don't spread yourself thin?