To look sharp is to look nice, classy. I think that's what you're referring to. If your friend shows up one day in a nice suit and tie, you might say "Wow, Eric. You're looking sharp today." But "look sharp" can also mean to act or move fast, to hurry up. "Look sharp, boys! They're headed right for us!"I don't know the reasoning behind that one, though. It's just one of those things, haha.

Эта фраза "to look sharp" имеет два значения: 1. You have to look sharp. - Вы должны глядеть в оба. Не прозевать! Держать ухо востро! 2. You had better look sharp, if you want to be in time. — Вам следовало бы поторопиться, если вы хотите попасть вовремя.

It means that we look fashionable/up to date