For stylized texturing techniques, see the tutorials here from Fanny "Faf" Vergne: http://wiki.polycount.com/wiki/EnvironmentSculpting Also the modular set Pirate castle [UDK] https://polycount.com/discussion/91066/pirate-castle-udk/p1
I find it helps to start with the trim sheet texture first, then model the modular pieces and UV them to that sheet. This way I can reuse already-UVd pieces to build up the asset faster. We have some tutorials here that might help you. I think the most relevant ones might be the first one by Tim Simspon, and the third one…