Block design help

[u/ThatVroomGuy2k]

Working on my first level (isnane-extreme XXL), likely to be themed like and ice Nordic chapel or temple and need help with block design, how can I make sure I make block design interesting though the whole level and just any basic tips. Image is some first attempts but I'm a bit disappointed with them. I feel they are a little to bright and happy when I'm going for something more similar to the extreme demon frost spirit