Playing around with textures in Photoshop.
I mean, it's just too fun. I've found that textures just give a picture a whole different feel. And (and this is helpful for me!) they can smooth over what is otherwise a mediocre, potentially out of focus shot.
Choose a different texture for the same picture, and everything changes. I like that.
And really the process is very easy. Armed with Photoshop and some basic instructions/tools (see links below), it's really do-able.
Also great for portraits.
Helpful texture links:
-One from PW's website, although a guest blogger wrote it.
-Download free textures! - and check out a helpful tutorial
-Texture sharing group on Flickr