I shoot a lot at daybreak in the mountains, and setting up before daybreak presents the challenge of focusing the subject in dim light. I have found that by ensuring all filters have been removed and really concentrating, I can get a pretty decent shot. Of course this is because the light is slowly creeping in at sunrise and I can use some reference points to focus on. A while back I was in Canmore for a weekend and had a great opportunity to photograph the 3 Sisters with a full moon behind them. This was in pretty much total darkness. Despite the fact I thought I had focused in nice and tight in the minimal light, I was quite disappointed in how poor the quality of focus was when I uploaded them. We do have property in the mountains where I have been able to set up my camera on tripod in daylight and focus in beautifully, then returned to shoot at night. An awesome concept, but I can't really leave my camera out on public land for hours waiting for darkness, I don't think it will last long.
I would love to hear any tricks or methods you could share on this subject.