All digital cameras have a sensor inside them and sensors are notorious for collecting dust over time. Eventually, you will probably need to have your sensor professionally cleaned but you can minimise dust build-up in the first place by making sure you only change lenses when your camera is turned off. This is because the image sensor produces an electric charge when your camera is on, which can actually attract dust.
Know your AF points
Modern digital cameras, and particularly DSLRs, often come with a bewildering number of AF points and ways in which to use them. Obviously, these are all very useful but your central AF point will always be the most sensitive. Plus, it’s probably also the most useful! It’s worth making a note of your cross-type AF points as well, as these are where two linear sensors cross each other – meaning the point works with both vertical and horizontal light patterns.
Read the histogram
Too many people rely on the camera’s LCD screen to ascertain if they’ve got a correctly exposed image. But LCD screens aren’t accurate. If you want to accurately assess your exposure on your camera, you’ll need to use the histogram. The main thing to avoid is clipping the highlights and, less importantly, the shadows. If your histogram is hitting the right edge of the scale, it’s worth reducing the exposure and shooting again.