(one's) best foot forward
A phrase used when one is trying to present an ideal version of oneself, typically to try to impress others. Often used in the phrase "put (one's) best foot forward." You really need to put your best foot forward in the interview if you want to get this job.
best foot forward
A favorable initial impression: He always has his best foot forward when speaking to his constituents. Put your best foot forward during an employment interview.