Tips for Large-Scale Terrain

Just as the title states, any tips for large-scale terrain usage?

I’ve used terrain a lot but sometimes I feel like something is missing. How can I make a lot of terrain and make it look good/realistic without needing any 3rd party tools?

I currently use part-to-terrain to make large amounts of terrain in different shapes but maybe it’s not the most effective way. Any tips will be greatly appreciated.

Designing terrain in blender and converting to mesh in studio I found has been a super effective way of getting nice looking terrain.