Hmmm, i see u like cars, u should tottaly color online man
Your art is amazing, but chalk isnt the best for coloring cars,
Personaly i hate coloring pictures myself, everytime i make a great drawing i want color, then I screw up coloring, and I have to start all over D: and the crayons, chalk, ect make it look funneh, i prefer fancy colored pencils XD but still not the result I look for :\
Just a tip of advice, other then that, You got skill dude