The same way everyone else does.
Don't be the tool who shows up in a cream Zegna 3-piece with obnoxious double cuffs and links, contrasted collar, tie rods, purple socks, and $2000 square toe loafers. Anyone who has been on a med school interview knows the person I am talking about. There is always one and they stick out big time in a very bad way.
Likewise, don't be the guy who shows up in baggy Gap khakis, flip flops, wrinkled shirt, and a crooked bow-tie who looks like he woke up on the floor less than an hour ago. There is also one of these in every group.
Jeez, it's not that hard! Black, blue or gray two-piece suit, black shoes and belt, conservative shirt and tie. Shower, shave, and comb your hair.
You want the people who interview you to remember your ability, not your ridiculous outfit.