How can I be as cool as Aragorn?

Well, there are several things that make aragorn super cool.

First, he has decades of experience in the world. (he is 87 and he spent 67 of those years wandering in the wilderness and learning what it meant to be a king to a fallen people). All those years he spent taught him a great many things; how to survive, how to heal, how to read a trail, how to track, to hunt, restraint, wisdom, etc.

Next, part of the bloodline gives him the ability to read the hearts and minds of lesser men. All those in the dunedain line have it (which includes the line of Stewards, though their line is less pure). Which makes him mildly telepathic. He also has a kind of second sight. He told Gandalf before entering Moria that his fear of going into that place was not for the company, as he knew they would survive, but that if Gandalf entered the shadow of moria, he would not return again. He also has incredible inner strength. He stood against Sauron himself in the palantir and won. He wrenched the gaze of the seeing stone from the eyes of the Dark Lord. NO ONE else was able to do so...not even Sauruman who is a demigod.

So if you want to be as cool as Aragorn, you've got some big shoes to fill.

Walk around with a cloak and a sword on your belt in public.