One of the simplest things a person can do to improve their images is to look over the scene where they are shooting, before taking the picture. The things to keep your eyes out for are wires in the air, pieces of garbage on the ground, or anything else that will mar an image when it is viewed at a larger size.
Often these small details won’t be very noticeable when taking the picture or reviewing it on the cameras screen, but often when viewed at a printable size, they can be very distracting and dominate the image more than you would like. Yes, it may be possible to crop the offending bit out later on your computer, but sometimes that will mean cropping out other important elements. Other post production tricks are cloning and stamping in Photoshop, but this could mean a considerable amount of computer work.
Often, just taking a few steps in one direction, or crouching down can eliminate low hanging wires. Or a few seconds to pick up and dispose of some trash. Save yourself extra work and the risk if having to crop a new composition by focusing on the image when it’s in front of the camera. You’ll thank yourself later.