If this is your first visit to Mull it may also be your first encounter with single track roads. They can be a bit daunting at first, but you'll soon get the hang of it if you follow the code. Think of them as very short stretches of twin-track road, and you'll avoid most of the pitfalls.
Passing places occur frequently. Most are marked by a black and white banded pole, although some have the newer diamond shaped reflective sign which is easier to see at night.