To look like a poser - I mean gangster - you need to thug out your riding stance to the max. An absolute minimum of 25" stance width. Anything over 26" gets bonus gangster points. Because everyone knows that the one with the widest stance width is obviously the most gangster. It doesn't matter if you're only 5'5", anyone that's a real gangster should most definitely have a 26"+ stance. If you can somehow get a 27" or 28" stance width, you will be the KING of all gangsters. Drill holes in your board if you have to - but get that stance width out there as far as possible.
Now that your stance width is gangster proper, you need to dress the part too. Every gangster knows that properly fitting riding gear is for 2-plankin' bitches or gay emo kids. Your snow pants crotch should, at all times, be at or below your knees. Also, a true gangster's jacket will definitely need to be at least 2 sizes too big. Better make it 3 sizes for that extra bit of gangster steez on the hill. 5'5" and 120lbs - of course you need an extra large.
BTW, a little secret that most wouldn't tell you is that if you ain't rocking Technine, you ain't gangster. In fact, the more Technine gear you have, the more gangster you are. Technine bindings, board, jacket, bandana (a bandana is a must) and pants are almost so gangster that when you ride by people in the park, their heads will explode from gangsternes overload that comes from being near you.