When I started out on this drawing I was just going to draw a tree. Nothing else, just a tree. As you can see things kind of took off from there. There was no plan.
Typically when doing darkness in pen and ink such as the night time sky here, it is done in a crosshatch method. One makes a series of short vertical lines then goes back and crosses over those lines with short diagonal lines in one direction, then repeat in the other diagonal direction and you may even add short horizontal lines to make the effect even darker. This is a quick method of creating black, although it may not seem so, but you can rapidly make those short lines repeatedly.
I started out on the night sky with the intent on trying crosshatching for the first time even though I am not a fan of it. I got in the second row of vertical lines, and knew I would not be able to bring myself into crosshatching them since I don't care for that technique. I tried something different - vertical lines only throughout. It was a tedious and laborious process placing lines within lines without crossing any and if I like the end result or not, I am not so sure but the journey to get there was fun...for me at least. (that last bit I'll enhance upon on the next drawing I post)
The foreground was an entirely different process which was even more enjoyable to do and I think would have worked better for the sky than what I had already done. It was all one big experiment just to see how things would turn out. Now I know, good or not so good though, that I do not know.