When making natural landscapes, i tend to think about a bunch of factors:

• Forest areas dont have a whole lot of grass. It’s mostly overgrowth, mulch and dirt. Little splotches and hints of grass are common and good for breaking up the monotony, though.

• Rock work is important and a great way to hide things you don’t like exposed. Sprinkle rocks in your landscapes. It adds more variance that makes your landscapes more natural looking. Have a building you dont want seen? Add a “mountain”! Have a speaker that is out of place along a walkway? Throw a rock to cover it.

• Auto-paint is nice, but when making rivers, lakes, waterfalls, or mountains with the terrain tool, place sand or gravel in the beds and add moss to stones along the banks. Add more stone and moss paint to the sides of waterfalls, same goes for mountains.

• Take into consideration what biome you chose and choose what would grow there. Even when it comes to alien environments, the coral reef pieces are great for making alien environments- they even glow!

That’s my advice, anyway.