You have to bite your jersey when resting or at the line in the clutch, you must always keep an intense face, after every big shot you hit you have to fist pump and stare down, when the media interviews you have to let them know how much of a badass you are, also very important never pass up a game winning shot even if you are doubled, even if you are struggling, even if you have little room to operate. It doesn't matter how many GW's you miss, the casuals will only watch highlights of your makes. It doesn't matter if you hurt your team bricking all 4Q or even game as long as you hit a tying shot or game winning shot.
This is how you get the reputation of a killer. Having the best elimination games of All-Time, having the most playoff GW's of All-Time, leading the league in 4Q scoring on ocassion, none of this matters.