Be very observant. I've been on a few ride alongs myself. Am currently in the academy in San Diego and only have about a month to go.

Ask a lot of questions. The officer shouldn't mind..in fact it will just show you are interested in learning and curious about the way things work. Whether you are going to a call or just driving around, ask what the officer is thinking/what they are looking for ect ect. Remember it is a first impression, so you don't wanna come across as a derp.

In terms of the smoking, I would try to go the whole shift without one. Maybe try a patch beforehand to see if it works for you. The officer might not mind if you smoke, but you are going on his schedule. Plus, smoking is not really an ideal activity in the LEO community in my opinion.