SMMeade hits the nail on the head. During hang, focus, etc. it's all about the ME working with the LD. Once the show is running, though, coordinating electrics activity with the SM is critical.
If as the ME you are also the board operator, it doesn't hurt to look at the show once in a while. Although plenty of SMs have an eye for weird-looking cues (e.g., "hey, one of the side lights is out") we also have lots of other moving parts to keep track of. If the ME can spot and repair an issue before SM catches it, that's great.
If as the ME you are the de facto sub for the board op, or for a spot op, it's great to shadow these tracks before crunch time. Become familiar with any special parts of the show. Knowing that XYZ song is fast and jumpy with a bunch of false exits, or cues 101-137 come so fast you won't hear cue numbers, will be helpful to you and to the SM and cast.