I don't know, I generally tend to like more studies then definitive pictures for a huge list of reasons :') it's always super interesting peeking through sketchbooks or seeing what an artist considers an early stage of work.
I particularly love how light works on the first picture but also the compositions of #2 and #3 are so great?? aaaaah <3 ;-; so nice!

Yeaah I know, I love too the fresh air of the sketches,but for some reason I don´t feel my digital sketches as "fresh" as my pencil ones, this is why I am now doing more fast works on digital and paint over a pencil drawing, maybe this way I´ll start to feel digital more natural in order to render more elaborated pieces.
By the way If you are interested on the composition of the pictures, I take the reference from a random google street view generator which is really useful for this kind of fast work (no more than 20 minutes for piece) but I put the colours in order to get better in colour values and so.

Those studies looks super good, indeed :D but I can understand why you're going for more practice, I'm doing the same with materials.
and that's... actually a super useful thing to know O: thanks for sharing!!