Exploration is one of the three pillars of play, and is one of the most fun! This is where you get to create a sense of wonder and surprise in your stories. Good exploration can really make a game. Here are a few tips to think of the next time you run your game.
1. Don't Describe Everything
At least, don't describe everything right away. Good exploration is a back and forth between you and your players. Describe the situation but try to keep this to three sentences or less, otherwise your players will be overloaded. Then let your players interact with those details. As they ask more questions, they start to discover more information about what's around them. The true key is to give them leading ideas, and then allow them to follow up on those ideas.
A Situation. Let's see how this plays out in a game. The party swings open a door and you give your three sentence description: "A glowing orb floats in the center of the room. There's blood on the floor. A obsidian dagger lies thrown in a corner." The follow up of such a situation might be:
Player: "I investigate the blood on the floor, do I see anything interesting about it?"
DM: "It looks like there is a trail of blood leading from it, like footprints of something large has been through here."
Player: "Do the footprints lead somewhere?"
DM: "They lead to the center of the wall and vanish."
Player: "Hmm... Odd... I bet there's a secret door there!"
I hope you can see how this interaction is much better than: "Roll a perception check... 17? You find a secret door." Notice how the description omits details, but you get to fill those in later. This is one of the keys to fun exploration.
2. Be Careful About Checks
To follow up from A Situation above, checks should be reserved for those situations that you feel they are completely necessary. In other words, don't call for checks when you think a normal person would see or find something. Calling for checks can break immersion and stop the flow of the narrative. More importantly, exploration is where you give your players information that helps their decisions and builds the mood of your game. You don't want your players missing out on the information that they need to make the game interesting and fun.
3. Describe what the characters find, not what it means
Let your players draw their own conclusions. Some players might want you to spell it out for them, but you shouldn't default to this right away. They may draw incorrect conclusions, but this generally corrects itself out over time. In some cases when they draw incorrect conclusions, you might just decide that that conclusion is cooler then what you have planned!
In this way exploration plays out like a puzzle or riddle. The players continue to ask for information and you provide more and more. They begin to discover more about the situation at hand. Just like in A Situation above, the GM didn't say: "the blood leads too the wall and disappears. You think there's a secret door there." She let the player draw that conclusion, which is part of the fun of exploration in the first place. The player may have asked other follow-up questions before figuring it out, but these would have all pointed to a secret door.
4. Give your players meaningful choices
When there is a fork in the hall, you need to give players some clues to help them choose a direction. For instance if a gelatinous cube is in the hall to the right, the floor might be oddly clear of dirt and debris. If a caged dragon is in the hall to the left, there may be marks of something dragged through that way. This way players get to have a choice, rather than staring at each other for a few moments till one of them blurts out "we go right!"
5. Think Backwards
The best way to generate these clues is to know what's ahead of the players and then thinking back to what clues might be left behind. If bandits are using the dungeon as a hideout the characters might find boxes of supplies, humanoid footprints, the sound of voices talking down the corridor. If the bandits are working with an evil wizard to summon a devil, you might find vials of blood in the supplies, hear chanting, or discover/trip magical traps set to protect the area.
Wrapping it up
GMing exploration is definitely more art than science. I hope a few of these tips helped you re-think how you're running exploration in your game. Have any more tips for exploration? Let me know in the comments!