The basics

Important!

This is, like all other photography guides on this site, a guideline, not an absolute rule of 'do this or your shot will be bad'. In photography there are no rules, just guidelines which can help you avoid pitfalls. These guides are meant to explain why certain aspects work and once you know why these work, it's up to you to use them to achieve what you're after, or go against them if you want to achieve the opposite.

This small guide will explain a common set of basic aspects of (virtual) photography which can help you understand why some shots work better, are more interesting to look at, than others. Some of these basic aspects are discussed in more detail in their own guide. If that's the case a link to that guide is provided.

Keep in mind that these are guidelines. You don't have to match each and every one of them before your shot is great.

Helpful tips

The subject

Define a main subject
One key aspect of interesting shots is that they usually have a main subject (only shots where the absence of a subject is the goal don't have one obviously). If you can't answer the question "what is the main subject", you might want to introduce one, as the subject is what the shot is all about.
Avoid multiple subjects
In general the viewer should have a clear idea what the subject is of your shot. If you have multiple subjects, the shot might get confusing to look at: if a shot as two subjects, is the shot about the first subject or about the second subject?
Frame the subject properly
If the subject isn't properly visible in your shot, the viewer might have a hard time figuring out what the shot is all about as the subject isn't really prominent
Make sure the subject is well lit
Look for light in your scene to place the subject so it's well lit and visible. Having your main subject in the dark while other areas are better lit will result in confusion as the dark area won't be seen first and the subject therefore will be missed.
Place the subject after the foreground and before the background
Most shots use a foreground, middle ground and background. Start by placing your subject after the foreground and avoid making it part of the background so both foreground and background are in support of the subject. Foreground can be optional, as some types of shots don't have a foreground.
Try to place the subject off-center
The well-known Rule of Thirds can greatly help with placing the subject at a place in your shot where it will be the most pleasant to look at.
Use negative space to your advantage
Whenever a subject is moving or looking in a direction, there should be plenty of space in the image ('Negative space') to allow the viewer to participate. For instance, if a hiker is walking toward the right, he should positioned close to the left edge.
Make the enemy bigger than your subject
In action shots where your subject is fighting a big enemy, place the camera in such a way that the enemy really looks terrifying. This brings more drama to the shot

Edges and backgrounds

Busy backgrounds
If your subject is placed in front of a busy background, looking at the shot will likely be less pleasant as the background will draw attention away from your subject. Try to use a Depth of Field (DOF) shader to blur the background so your subject stands out more. Keep it simple usually works very well.
Bright spots (non-bokeh) in the background
Bright(er) spots draw our eyes to them. If you have various (larger) bright spots in the background, it'll draw attention away from the subject.
Try to keep the edges of your shots fairly simply
The edges of an image are a sensitive area, and there shouldn’t be anything too prominent there, lest the eye be tempted to wander off. Cut-off objects are also to be avoided.

Colors, lines and shapes

Try to use colors to direct the attention of the viewer
Colors can direct the attention of the viewer to certain areas, e.g. the subject. Try to use color theory to your advantage and e.g. use colors from your scene to drive the color choices in reshade shaders you're using, or even which armor to wear on your subject.
Use leading lines to guide the viewer to the subject
Leading lines in the scene, e.g. a railway, a set of lines, a path on the floor or objects forming lines in the scene will lead the eyes of the viewer. Move the camera so the lines lead into your shot and place the subject close to that area so the lines lead the eyes of the viewer to the subject.
Look for triangles and shapes
Strong shapes, especially triangles and diagonal lines, look dynamic and direct the eye. Positioning the subject at the intersection of strength lines is a powerful method of attracting attention to it. Using natural frames (tree branches, arches, etc) also works well.

Camera aspects

Avoid a high field of view (FoV)
Games are often displayed using a wide field of view (FoV) sometimes even close to what a fish-eye lens would provide. While this might work great for the game, it won't work that well in many types of shots. Try to avoid a high FoV by zooming in a bit. This will remove some elements from view, but it'll also make the viewer focus on your subject more. One exception for this is landscape photography as landscapes are often shot with a short lens which gives a high FoV.
Remove / disable the vignette effect
While vignetting in shots can draw attention away from the edges of the shot, having a (strong) vignette in your shot when you take it will make it hard to alter it later on in e.g. post-processing.
Use the aspect ratio that fits your subject
If your subject is a tall person and you want to have it completely in-view, usually an aspect ratio that's more higher than wide (e.g. 2:3) is preferable over an aspect ratio that's very wide (e.g. 21:9). On the other hand a wide vista of a landscape is better served with a wide aspect ratio than a narrow one.

Tricks

Use alt-tab for checking your shot before taking it
Using alt-tab in windows will usually give you a smaller view of the game window, and this smaller view on your shot will instantly reveal if you made a mistake placing your subject; i.e. if the subject is barely visible in the smaller view, chances are the subject 'drowns' in the shot and it'll be confusing what the subject really is
Take the shot at a higher resolution
Even though image quality shouldn't be more important than composition, it really helps if your image is sharp and doesn't show a lot of rendering artifacts.