“Be yourself; everyone else is already taken.”
Only you can be the best at who you are. No one can beat you at that game.
On the other hand, trying to mimic the mannerisms, behavior, style, etc. of others, will never get you far. You’ll always be the poor knockoff version of the original.
E.g., if you like a certain type of music that none of your friends in your social circle like, don’t try to pretend that you also like what they like. Embrace 100% of who you are. Everything you say or do is cool because it comes from you, and you set the standard of what is cool.
Makes sense? Look at this way: if you’re trying to be cool (standards set by others), you’re basically by definition not cool.
Find your uniqueness and focus on that.