The art community has a basic rule when designing an image. Divide your surface area into a 3x3 grid, and place your object of focus on any of the points of intersection.
Asymmetry appeals to humans for a reason I don't recall at the moment, so to place something dead center, while is certainly acceptable and sometimes advisable, might give off a boring feel to it, while having a character in the mid-lower-left corner might really catch someone's eye. These four points on an image also act as focal points, and it helps to draw the viewer's eyes exactly where you want them.
Notice the red circles (Or "hotspots") these are the natural focal points of an image.
For more on this, see <a href="http://en.wikipedia.org/wiki/Rule_of_thirds">here</a>.
This may seem obvious, but this can completely RUIN a box idea, and no matter how cool or original your idea is, if a character isn't consistent with its surroundings then I would say that the project is over before it was even finished.
This can be avoided by actually altering images you have on-hand. Maybe you have a cel-shaded character image, and a realistic one. With enough time, effort, and knowledge of photoshop, that realistic character can be converted to look more like a cartoon. Problem solved! This logic can also be applied to backgrounds.
The first major example of lack of cleanliness is cropping an image. Having ugly, jagged, white pixels (Or any off-colored pixels for that matter) surrounding an image is a massive turn off. There isn't any excuse for having them, as even the most rudimentary photoshop capabilities can fix this problem with patience. Another issue with this is blurriness, or Jpeg artifacts, often the result of low quality images, or more often tiny images that are stretched to fit a larger box cover. Photoshop has a few filters and tools that can clean up an image, but it's better to just find a higher quality image in the first place.
This is an example showing off the jagged edges, jpeg artifacts, and floating artifacts that didn't get erased that often come with newcomer's boxes. Taking extra time to clean up an image and make edges smoother can make all the difference in the world.
- Read tutorials, look for resource threads, and keep a collection of textures and miscellaneous images for future use.
- Not every cover has to be a picture of a character, sometimes it pays off to create a cover that helps illustrate the emotions a game conveys. A more symbolic route can often result in a more rewarding product.
- Hold the shift key (In photoshop) to lock proportions when stretching an image, this stops it from looking too fat or tall.)
- If you can't find a high enough resolution image, DON'T USE IT.Don't clip a character's image off on the edge of your cover, it's a dead giveaway that the work is that of an amateur.
- Gradients can look really cool, but often by themselves are boring. Adding a texture to a gradient can turn things in your favor.
- Don't place a character so that part of their body is being clipped off the side of the box. Rearrange your cover to sample different looks to avoid it.
Would anyone like to contribute?