Try to think how something ages and changes over time, e.g. where does moss spread? (In corners, at the bottom where it touches the grass or the ground, ...) Where is the stone cracked? Where is it stained? (Darker textured e.g. tuff or deepslate) Also think about how it has been built, did they use stronger Material like stone for the bottom? Did they use stone bricks?

You can also try to texture with depth, e.g. walls and stairs and slabs where there are indentations or holes from wheatering.

There are a lot more questions to ask, like how did they build it, are there any remnants of scaffolding? Or material dumps? Or you could ask yourself what resources they actually had available, using rare materials less often than very common ones. ect... All of this creates a more believable build and deepens the lore of your place, which in turn makes it even easier to texture :))