[spicoli]

be supportive and don't bring it up, let her talk about it if she wants.
some people need to replace the habit with something else that is a healthy alternative, such as going to the gym, or going for a walk when a strong craving hits. or just filling time with something she enjoys, instead, like reading, or making something. the trick is getting your mind to stop thinking about smoking, and on to something else. the cravings will pass. i was lucky, and when i quit, i was completely ready, and had no cravings.
good luck, really. it's a great thing to quit the cigs.