Batteries in the cold
Two spare cells live in an inside pocket now. At four degrees a full battery gives me barely forty frames, and the camera lies about how much is left.
Scouting before dusk
Arriving in the dark costs an hour of fumbling. Walking the same spot at golden hour, marking two or three compositions and noting where the tripod legs actually fit, turns the night session into something closer to a checklist.
Focusing on nothing
Autofocus gives up in the dark, and so did I for a while. Live view at maximum magnification on a distant light, then tape the focus ring. It is crude and it works every time.