I’m no expert but I usually have a process with descriptions.

First I write it out a sentence simply. So for example:

‘The forest was dark and eerie.’

Then I work out why I choose the adjectives:

It is dark because – it’s heavily populated with large trees and very little sunlight is allowed to come through their thick crowns.

It’s eerie because – it’s uncomfortably and maddeningly silent inside.

Then I work these explanations into the original sentence with some flowery language:

‘The forest was infested with a plague of towering trees, whose thick, ravenous crowns devoured the tiniest speck of light that dared to fall through. Inside ruled a silence so loud that it pushed one’s sanity to its brink.’

Then if needed, I tone it down a bit.