I like to provide my players with some visual references for the locations and events they partake in throughout our campaign. We can't sit around a table, but we can easily share images. Many of them I take from the books, but I've found that old paintings are a fantastic resource, and that a quick Google Images search can reveal all manner of imagery, much of which will in turn spark ideas for use in the game.
The players are currently crossing Mirkwood for the first time, and have sought refuge at Amon Naugrim, an old abandoned trading post and inn along the Men-i-Naugrim. I wanted to find some image to show them what the place might look like, but I couldn't find anything that matched close enough. But I did find an old crumbling tower, albeit with a variety of features I didn't want; and so I took to some quick and dirty Photoshopping. And voilá, the tower on Amon Naugrim.
Here's the original.
And here's a night version of mine.