what do you dress like now? If your wearing normal crappy clothes, go out and buy some nice dress-type pants, some good boots/shoes, I nice leather jacket, change the hair style, but some sweaters and a shit load of nice clothes...take a hot chick shopping with your she'll do you up with a good look most of the time.
If your wearing turtle necks and dockers then go for the more casual look...nice jeans, brand name shirts and shit.
Tattoos won't really change your look but you could do that if it'ssomething you want but haven't done.
If your old, go out and buy a motorcycle or a corvette or something and that will be your new person you wanted.