There are numerous “rules” of photography, many of which apply to shooting landscapes. There’s the Rules of Thirds, certain “must have” filters, the importance of paying attention to hyperfocal distance, and many more.
One sure way to spoil an otherwise nice scene is to frame the shot carelessly and end up with a crooked horizon or shoreline. Fortunately there is a quick-and-easy fix if you understand how to use Photoshop’s Crop tool.