One thing that I have not seen (somebody may have said it, if so I apologise) is that, in the air, select carb heat ON before reducing power - a good 10-15 seconds before doing so. Failure to do so (if you have ice forming in the carb and don't yet know it) will result in the ice jamming your throttle butterfly valve closed and, when the donk dies, you will have no means whatsoever of resurrecting it as the exhaust manifold will also have cooled by then.
I concur with those who say don't use carb heat while taxying. Use it on the ground while stationary by all means.
Check the graph in the books of temperature drop in the carb and the range of OAT's that will therefore most likely result in carb icing outside the green arc.
As for the rest of it, don't follow what Bob in the cafe told you he does. His aircraft is probably different from yours. Follow what your instructor told you and (hopefully) the POH also says.