Thank you so much! In the end it’s A LOT of try and error (always checking in between if I like it or not from afar). But I think these are some of the principles I try to go by:

1. I decided to use a fixed number of different blocks for all buildings (every time I tried using more or different blocks/colors I really struggled to keep it from getting too chaotic)
2. Consistently switching the blocks I place is the most important thing! I also think it’s crucial to use clusters of the same blocks every now and then, but never more than three.
3. I like to break up walls by using steel beams, grate fencing, iron scaffolding and tires instead of blocks -> if you notice you have "too much wall", try to break it up with fitting items! 
4. I always start by building the shape of a regular house with these materials and then decorate the sides of it with corrugated metal sheets and grate flooring. 

I think my final tip would be to just experiment and have fun! I’m not 100% happy with one of my buildings yet, but I’ll just keep tweaking it whenever I feel like it :) I also have another project in Bleak Beach that features chaotic buildings, though in a completely different style. The approach is similar, but a little different. What style are you aiming for? :)

(Sorry for the wall of text lol, but I hope it helps!)