Nice first diorama.
Advice-well lets start here.
The base is well done, not just a square block. The road is angled giving visual interest,.
Composition is good, easy simple and effective, recon unit reporting back. There isn't a ton of empty space.
The builds look good, nice and clean, not gaps, or major flaws.
If I were to suggest anything I would suggest a dusting pastel in a light dust color. This is an early Tiger, in gray color so it's more than likely in Russia and these guys got used a lot and got dusty all over. I would use a very soft very large brush to apply the dust coat. I would unify the ground and the vehicles using this dust and dust everything.
As Chas mentioned, better foliage would liven this up. If all you have available is lichen, I would get some spray glue and parsley and at least add a touch of the glue and sprinkle parsley on top. Lichen alone tends to look like a railroad layout from 10 years ago.
Lets see the next one come to life. Ask any questions you may have.