Textures on the outside:
You should avoid the textures clash between 2 different brick textures, add details to make it two separate buildings.
Textures on the inside:
You have use a fabric texture on the walls and it look very odd indeed.
The choices of textures is actually the main problem with mappers.
My advice would be... Avoid scrolling through the 246 different textures while editing!
Instead, while you are making scketches for your map, open you textures folder and choose them there, picture it in advance in your head how it should look like.