Written for Malachain: the essentials, without the noise.
The aspect ratio is the relationship between the width and height of an image. Most modern televisions use a ratio of sixteen to nine, but many cinema films are shot in wider formats to fill a large screen. When such a film is shown on a television, black bars appear above and below the picture so that the whole frame remains visible without cropping.
Older television programmes were made for nearly square screens and may show bars at the sides instead. Stretching or zooming the picture to remove the bars cuts off part of the image or distorts faces, losing what the director intended. Setting the television to its original or automatic picture mode usually shows each programme in the shape it was made.
The most useful step is usually the first one. Pick a single suggestion, try it for a couple of weeks, and then decide whether it is worth keeping. Small, steady improvements last longer than ambitious plans that are hard to maintain once everyday life gets busy again.
It also helps to talk the subject through with friends or colleagues who have tried something similar. Their experience points out the details that guides leave out: how long things really take, which costs were unexpected, and which shortcuts turned out to be a mistake.
There is more to learn on this subject, and the linked website goes into greater depth. Treat this article as an introduction rather than the final word, and check any important decision against up-to-date, reliable sources before relying on it.