I would tell you a thing...(don't be mad at it because every person has the same mistake)
you should make the direction of the sunlight before you start shading!
so, for example, if you make the sunlight coming from the right side, then the left side should be shaded more!!
(if you are trying the background, you can choose from two)
1. you can make a background with grass and then draw some jail thingys and make some people behind with an interesting pose!! they can even fight too :)
2. just make the background gray and then shade the shadow part and draw some things to express the jail!! (the shadow part is ... uh... look at the url I give)
https://anime.kenmaz.net/anime/show/5293750
