get all the areas of your face, but this will get easier the more you practice. keep in mind that most guys have hair that grows upward on their necks, meaning there is a line where this upward growth patter meets the majority of the downward growth. make sure you shave with or across the grain in this area. most people will break out on their necks if nowhere else because they continue to shave downwards on this spot.
a second pass can be done if you're not that sensitive. some people like to shave against the grain on this second pass, but even most barbers will typically just shave across 