[vespine]

I've also only just started observing and have been thinking about similar questions to the ones you raise. Observational logs are mainly for your own benefit so just write them in a way that makes the most sense to you. I also think keeping a log aids you in getting the most out of your observing session by helping you to learn how to appreciate what you are looking at by honing your "seeing" skills. The way I believe this happens is by purposefully paying attention to as many aspects of what you are seeing at as possible, as opposed to just looking. I liken the analogy of seeing as opposed to looking is the same as listening as opposed to just hearing.
The 'formalities' I include are date, time, telescope used (even tho I only have one for now you never know when you'll get a different one), temp (on a scale of warm, cold, very cold ) I then mention if I have planned targets or just ad hoc observing. This can mostly be done in about a minute before even going out to the scope.
Then I think a great way to start after setting up the scope is by gauging the seeing on that particular night. This is something that I'm still not very good at, but I generally start by writing down how transparent the sky seems and how much stars seem to twinkle, near the horizon and right above. This is my 'simple' gauge of how good seeing is until I learn how to do it more formally, the more you do it and record it the better sense you will get of how good a particular night is, which I think is a good skill to have.
From there it's really just up to you, I'm still learning a lot of the constellations and only know the names of a few objects so most of my logs are not very accurate with that information, but the more I find and identify the better I'll get at it, which I guess is the point.
I'm at the stage where I'll find something and try to spend several minutes looking at it, at first it seemed like a bit of waste of time since initially it feels like "once you've seen it, what's left to see?" but you really do start seeing a lot more when you spend more then a couple of minutes on one object, particularly with nebula I find. When my eye starts getting a bit tired I'll take a rest and usually have a look through my binoculars for a minute or two and then I'll go back to the eye piece for another few minutes. Then I'll change eyepieces or use my barlow and try to describe to myself any differences I can find in how much I can see.
Last time, I even had a shot at drawing the jewel box just to have a go, I found it quite difficult, I might actually post in a new thread and ask for some tips because it seemed like something I'd like to keep trying. It really helps you to try to actually SEE every single star/detail instead of just looking at it like one object.
Anyway, this post has turned ridiculously long! So I'll leave it there