One of the fun things I like to do is treat the edges of the paper. I've done this before on this blog in my sketchbook in the past. I am planning more edges but here is what I have so far.
This one was done with a sheet of paper as a mask along the edge. I laid down some graphite then smeared it with my finger towards the edge of the paper. The little marks are ink "stitches".
This edge was just scalloped then pierced with a hole puncher. I have done both of these before but I never get tired of doing them.