Well, the first thing you need is a ridiculous costume. The more garish the better. Remember, the only people that get it right on their first try are idiots. If possible, it should clash with everything down to your skintone. If it could somehow clash with itself, that would be great.
Next, well, you've got to join the union.
Then you stake out a city. If you live in London or New York don't bother, but if you're anywhere in the midwest it usually goes about one per customer. Batman had Gotham, Supes had Metropolis, and believe me, you don't want to be the sucker stuck with Trenton.
Lemme think. All right, so we've made sure that you look like a retard, you're paying your dues, and you're casting a watchful eye over Gary Indiana. You'll probably want a code name, one that goes along with whatever your schtick is. Be sure that you pick one that you like, because otherwise you'll spend the rest of your life being called Beast Boy.
Then you start hitting people. If you're lucky, you'll get good press out of it, and you can use it to get tail. Otherwise you'll end up like Batman and thought of as a myth propagated by the liberal elite to patronize and demean the working man, to quote from something or other. Do a Google search, it'll come up.
And if you've read this far and haven't figured out that I was joking, then you shouldn't be a superhero. Otherwise, congrats! You passed the first test.
What's your schtick, anyway? Martial artist detective? Alien from a far off land? Last of your tribe? Displaced time traveller? Come on, give us some details.