Only smoke when you're around other smokers. (I have two close friends, one who smokes along with her whole family, and one who doesn't smoke but his parents do, as well as a smoking coworker, so my mom is used to me coming home smelling like cigarette smoke.)
Wash your hands. Even if you have the friends excuse to explain your clothes, your hands will smell like it and that's a lot harder to explain away.
Chew gum, use breath sprays, or brush your teeth if possible.
The best option is to try those new dissolvable tablets. Then there's no smoke to hide at all. :) And you're not killing your lungs that way.
Although I would highly suggest not smoking if you're underage. I'm of legal age myself, but don't let my mom know because she has enough stress in her life and I don't need her worrying about me.
DONT SMOKE IN THE FIRST PLACE, EVEN IF YOU ARE OVER AGE! Your friend is stupid, "smoking alsong with her family?" What the heck?
you can't you just take pills for smoking and try to stop smoking and quit
Update by Devil Man:
I can tell you two things.
Smoking isn't good for your health.
If you are having to "hide it" then you shouldn't be doing it in the first place.
Why hide smoking? One day, when you start dying or getting a disease, you will be sorry for ever smoking. I am right, you'll see.