The objective of this article is to give you some useful tools to ensure that, when the potential buyer looks towards the array of games on the shelf, your game will be able to capture his the attention, because it will stand out from the others.
In order to have an effective box, here are 6 key points:

1) Document yourself on the competitors and the market. 

Some marketing choices that we could make on the realization of the box are in constant relation with the market trend; therefore avoid, at least for the first experiences, to think too much outside the box. 

The first thing that is good to do is to take time. The desire to immediately start messing around to come up with what will be the graphics of the box is great, but first there must be the boring, but necessary, part of research and study. But why? 

We want the game to respect and communicate its uniqueness in the best possible way, so get yourself to work on a graphic and then discover that in the end it is very similar to that of another game, maybe even more famous, does not benefit the project. The advice is to open a search engine and start researching by type of game. This is fundamental especially if your goal is to publish the game with a publisher. Look carefully at his titles, because the box will probably be found next to those games. 

2) Simplicity and clarity.

In the part that acts as a cover for the box, that is its façade, it is necessary that the image is not chaotic but that it communicates a well-defined message.

Example: The possible buyer at the fair is often in a hurry and, unless he is looking for your own game, he is passing by to take a quick look. Let's say that this person likes games inspired by the world of Lovecraft. His gaze will be captured by what will most easily communicate that it is inspired by that world. Even if the graphics of your game are technically better, it will not attract your attention if it is difficult to understand from the medium distance.

THE TRICK IS: take the image of the box and observe it at a distance of 15 meters, if it remains clear and understandable, you are well on your way. Remember then that the logo must be as clear and legible as the illustration.

3) Colors and mood.

Even the color can simplify the appearance of the box. Making contrasts between a warm background and cold-colored characters can help. Also on the distance verify that the image is not too dark and that all the elements remain distinguishable.
Mood means the atmosphere you want to give to your game. A convincing atmosphere is needed to get the game noticed. Also try to respect the typology.

Example: If it is a fun party game, choosing dark and cold tones is not the right way, because you want a family to look at the box and say, "it looks funny!", not that it's too serious. A target that loves dark tones instead, would be attracted to it, but then looking better and understanding that it is a party game it would be confused. Good research can help.

Case: Observe Sycthe. Here all the graphic elements are cohesive to give a well defined feeling. Watch the My Little Sycthe variant now. This communicates quite the opposite. What is the game for children and which is not? What is the game that seems to be lighter?

4) Content.

On the box it would be good to write what kind of game it is. If it were a card game, making immediately visible with a written "Card game", would help the player to get a clear idea.

Example: Exploding Kittens is a card game. On the box there are no images of cards but only a funny cat, but just below it is clearly readable "A card game". If the buyer likes card games and the image, the box will be taken in hand and viewed from the back.

The back must absolutely have an image that represents the contents of the box, as it must always be clear what the player will buy, but not only. In fact, observing the components can project itself during the game, the imagination and emotion increase the chances of a purchase.

5) Icons and technical details.

A box has always in evidence, both on the front and on the back, the symbols that indicate the playing time, the number of players and the age recommended. Moreover on the back it would be good to insert a phrase of effect on the game, which summarizes it and communicates its mood.

Another key thing to include is the list of components. It is important to affix the CE mark, thus declaring that the game complies with the directives of the European community. Still talking about marks, if in the game there are small components, such as dice or pawns, it will be good to insert the 0/3 year mark because it is dangerous for children who could swallow their parts.

Other details to put are: 1) the author of the game on the front, but not too big written. 2) Copyright on the back: by whom it is distributed, by whom it is produced and the barcode (NB. Every publisher or company in the sector will have its own directives to follow, make sure you understand them)

6) Graphic processing.

Choose carefully who will make the graphics of your game. Don't think it's always a savings to ask a friend who gets along with the graphics; the damage you could do is actually very big. A professional designer could help you find the right representation for your game, making you earn double and then making you return to the investment.

Hoping that the article was helpful, good luck with your game!