If you are with a group of motorcyclists, but you don't look the part, follow these steps to look like a dirty biker.

[edit] Steps

Carrying a baby will completely kill your image

Focus on the colors: Wear as much black and red as you can. It would look good on t-shirts, bandannas, your bikes, and any other items that would be easily visible.
Wear the right clothing: Leather pants, jackets, vests, gloves, all of these would look good and protect you in a crash. Get the gloves studded, and the jacket or vest with a customized logo on the back. Also, to keep the sweat out of your eyes (and you'll be getting a lot of it from your hair pommade), a bandanna would do nicely, sweatbands are an automatic butt- kicking.
Fix your hair: (Regularly) As for the hair, most bikers grow theirs out long. Most bikers will dye their hair bonnie black, dirty blonde, or brown. The hair is usually wavy, but not curly. So get a nice curling iron and learn how to use it.
Pay attention to the facial hair as well. Consider a handlebar mustache (stache wax is the preferred, so as to maintain that perfect coiffure after a hard days ride), or a long beard. Not so long that you look like Santa Claus, but long as in halfway down your chest. Just like the regular hair, most bikers will dye it the color of their regular hair color.