dont have tips sorry :( i have no idea what im doing with colours, as it is, but i can offer some impressions?

to me, it seems like they are in a room with poor lighting instead of a night time situation...

i like the poses and the composition of the piece, it conveys a story immediately. something has happened. person is hurt, and the other one's not doing too hot either, but he has to keep fighting..... something like that...?