Keep an eye out for lines, the kind that will lead your eye into the scene of the photo or even lead the eye past the scene and out of a photo. Leading lines can help to divide a photo or to unify, and it draws you into the photo at the same time. Leading lines can be straight, curved, zigzag. Think about train tracks, fences, curved roads, winding stairs. Anything that has a line of sorts that will help to draw the eye in and along it.