Photography Guide to Horizontal Horizons

Digital Photography School have published thier guide on how to take photos with a horizontal horizon, and how to fix the ones you got wrong:

"One of the first ever tips I was given when I began taking photos as a teenager was to watch the horizon when framing a photograph. The day after I was given this tip I went back through all of my photo albums (I was using film cameras back then) and discovered that a fairly large proportion of the images I’d been taking looked a little like this one."