Do nothing/not do anything by halves
Definition 1 of 1
Pro Tip 1/3Full Commitment
The phrase means being fully dedicated to an activity, leaving no effort spared. 
He renovated his house and didn't do anything by halves; every room looks spectacular.
Pro Tip 2/3No Mediocrity
Using this phrase suggests that doing things halfway or average is not acceptable. 
When she organizes events, she doesn't do anything by halves; they're always extraordinary.
Pro Tip 3/3Positive Connotation
It's usually meant as a compliment, praising someone's thoroughness or dedication. 
As a chef, he doesn't do anything by halves—his dishes are flawless.