Map-making advice: The one-look principle

I originally intended to write a three-part series about map-making. In fact, I nearly finished the second part and meant to post it before the top 32 reveal in RPG Superstar. But then it dawned on me, there's one single piece of advice that in my humble opinion trumps any other advice I could give.

My hypothesis is that in RPG Superstar, the first impression matters the most. If the voter doesn't fall in love with your map in 2 seconds, you've probably lost the game.

After all, there are 31 other entries and people are impatient creatures.

Below are some basic things every map should be, plus a few things specifically intended for contests like RPG Superstar, where the first impression matters much more than elsewhere.

Three rules every map should follow

1. It has to make sense: If it is an overland map, the placement of terrain types and biomes should follow the same rules as their real-world counterparts. Similarly, in a house, the kitchen is generally located somewhere near the dining hall for obvious reasons. Any room, building, or other map feature should have a reason to exist, and where they appear on the map should also make sense. A good way to inject some realism into your maps is to study real maps.
2. It has to be useful: Although the map round in RPG Superstar 2015 doesn't involve encounter building, your map should be conducive to building an adventure or encounter around it. For example, if your map is an encounter map, there probably should be an area suitable for a boss fight.
3. It has to be fun: The place the map depicts has to be interesting to explore, and there should be interesting terrain and things the PCs can interact with. I would argue that ultimately, the point of the game is to have fun, and therefore, some departures from realism (cf. the first principle, "it has to make sense") are acceptable if exploration or combat would otherwise be less interesting. For example, in real life it makes sense for most rooms to be rectangular (easier to build) and relatively small, but a square 10-by-10-feet room is not a very exciting place to fight in Pathfinder.

The one-look principle

1. It has to look exciting: The moment you see the map, it has to scream ADVENTURE!!! It is not enough that the location is exciting in your head or it requires several paragraphs of accompanying text to seem exciting. No. The map itself has to look exciting! If it doesn't, you've already lost the game.
2. It has to be easy to understand: If it takes more than 10 seconds to figure out what a squiggly thing on the map is or that there are actually huge differences in elevation, you may need to reconsider your map or at least change something in the way you present these map elements. A good key to the map helps a lot, but ideally, the map should be easy to understand even without a key.
3. It has to have eye-catching shapes: I recommend including a few big, eye-catching pieces of architecture or naturally occurring shapes. Big rocks, big statues, monuments, whatever catches the eye. Bonus points if you can fight on top of it. Actually, the entire map can be the eye-catching shape. For example, a dungeon that's actually the body of a petrified creature of truly monstrous proportions.