Beginner

Intermediate

How to Make a Rock Arch in Blend  ----------------- - watch this video first

Modular spaceship hallways

Cg Geek makes a out door environment 

he uses several techniques in some of his other videos.  Nicely done.

Build a Space Scene in Blender FAST – VirtualTweakers  -   Make some hero asteroids first though here.
So, this is good maybe for doing a quick space scene and putting the Enterprise in it.

Create a Realistic Forest in 30 Minutes | Blender 2.8 Tutorial -- with fog Great for establishingshots  - Make some trees first here.

Another forest scene using better textures, models Great for medium shots

Advanced

From start to finish.  He also adds nodes in the compositor tab for added effects that help the image look better.

He talks about how to import some sort of smoke simulation, that's baked. So it renders fast and keeps the viewport quick. Oh, wow, several good tips on this video.  The walk through camera mode is an ok idea, he then captured the motion (turned on automatic keyframe insertion, where is that he didn't say), that's cool and useful. Also that minecraft importer was awesome.   I wonder how he comes up with ideas like this.   I suppose a few sentences, and then fills out the idea.   LIke, Make a minecraft simulation with good physics.  He then figured out what he needed, Like the plugins, and then figured out the simulations, etc.

Create a forest with rocks, grass, foliage, and trees.