M9 metering was probably the biggest adjustment I needed to make. I think of it as a sort of wide centre metering, so it meters on whatever is in the centre of the composition. My usual practice is to aim at what I want properly exposed, half press and hold to lock exposure, then recompose and shoot. Focusing comes before or after depending on how much difference is between the exposure target and the scene; my usual habit is to focus first.
For evenly lit subjects it is fine to meter exposure on the centre of the scene, focus, recompose and shoot.
For scenes where the subject is very dark compared with the rest of the scene, you can either meter on the visual overlap of the subject and bright area, or meter for the subject and equalize exposure in post.
For a bright subject and dark background, meter on the subject and equalize the background in post if desired.