Personally, I love describing it like a book. If the party is going through an ominous forest, describe it as much as possible. For example:

The party travels arduously for several days, the dark forest looming overhead. They traverse through thick undergrowths, avoid snarling tree branches, and pick their way through as best they can while still keeping up their pace. Eventually, they arrive at the end of the trail, battered but alive.

Hope this helps :)