The common theme throughout these types of the questions is that the DM will generally only call out things that are important. So if the DM says, "there are statues flanking the stairs," that must be important. Your description should not be on just the things the players need to interact with, but with what their focus would be.

Describe how a rug is placed oddly in the room, that the cabinet sits with one door swinging in the wind, and the paint is flaking off the north wall. All of this has nothing to do with the story; it's just flavor.

"You open the door and see a rather chaotic room. Although the room is unlit, there is some light coming from the moon outside the only window not boarded up. The floor is mostly carpeted, except in the center where it looks worn away. There are upturned tables and chairs pushed to the walls, emphasizing the clearing in the center of the room. Sitting in the center of the room is a large, wooden table, very different design than all the other furniture in the room. The light from the moon almost seems to spotlight the table. It has no chairs near it, nor any objects upon its surface. What do you do?"

Turns out the table is completely normal and was brought in there on purpose by thieves. They placed it there to make it very suspicious so that adventures would waste time and spells. However all the thieves are hiding behind the tables pushed against the wall (less likely to be hit by Area of Effect spells), and a couple that hide behind the now open door. When a few adventures do finally enter, they slam the doors shut, and lock the doors separating the party.

Note how the description is keyed to the focus of the room. When the players enter the room, highlight what is obvious, and downplay the rest (mundane and threat alike). In my example, if you walked into a room with a single table, bathed in moonlight, with no furniture, not even the carpet within 10' of it, that is where the their perception will focus. I didn't NOT talk about the tables the thieves were hiding behind, but wouldn't be the perceived danger.

The key is to change up how you describe rooms. Drawing attention whatever is the focus of the room, and down play everything else.

"As you enter the ballroom, you are overwhelmed by the immense size. This grand room could fit the house you grew up in. Streamers litter the floor in a paper spiderweb. The chandeliers reflect the light from your torches across everything. The twinkling lights make it hard to focus. You can see a few dusty suits of armor to the south and north. There is a bar in the back where you can only imagine once held a buffet. Between the streamers, you can make out the tile floor a checkerboard of black and a light green; matching the drapes that cover the most of the walls. In the center you can make out what could be a dead body, partially covered by streamers."

Can you guess the threat?

It was the mimic disguised as the bar.

The common theme throughout these types of the questions is that the DM will generally only call out things that are important. So if the DM says, "there are statues flanking the stairs," that must be important. Your description should not be on just the things the players need to interact with, but with what their focus would be.

Describe how a rug is placed oddly in the room, that the cabinet sits with one door swinging in the wind, and the paint is flaking off the north wall. All of this has nothing to do with the story; it's just flavor.

"You open the door and see a rather chaotic room. Although the room is unlit, there is some light coming from the moon outside the only window not boarded up. The floor is mostly carpeted, except in the center where it looks worn away. There are upturned tables and chairs pushed to the walls, emphasizing the clearing in the center of the room. Sitting in the center of the room is a large, wooden table, very different design than all the other furniture in the room. The light from the moon almost seems to spotlight the table. It has no chairs near it, nor any objects upon its surface. What do you do?"

Turns out the table is completely normal and was brought in there on purpose by thieves. They placed it there to make it very suspicious so that adventures would waste time and spells. However all the thieves are hiding behind the tables pushed against the wall (less likely to be hit by Area of Effect spells), and a couple that hide behind the now open door. When a few adventures do finally enter, they slam the doors shut, and lock the doors separating the party.

Note how the description is keyed to the focus of the room. When the players enter the room, highlight what is obvious, and downplay the rest (mundane and threat alike). In my example, if you walked into a room with a single table, bathed in moonlight, with no furniture, not even the carpet within 10' of it, that is where the their perception will focus. I didn't NOT talk about the tables the thieves were hiding behind, but wouldn't be the perceived danger.

The key is to change up how you describe rooms. Drawing attention whatever is the focus of the room, and down play everything else.

"As you enter the ballroom, you are overwhelmed by the immense size. This grand room could fit the house you grew up in. Streamers litter the floor in a paper spiderweb. The chandeliers reflect the light from your torches across everything. The twinkling lights make it hard to focus. You can see a few dusty suits of armor to the south and north. There is a bar in the back where you can only imagine once held a buffet. Between the streamers, you can make out the tile floor a checkerboard of black and a light green; matching the drapes that cover the most of the walls. In the center you can make out what could be a dead body, partially covered by streamers."

Can you guess the threat?

It was the imps hanging in the chandeliers.

The common theme throughout these types of the questions is that the DM will generally only call out things that are important. So if the DM says, "there are statues flanking the stairs," that must be important.

To fight this, include the mundane along with the important. Describe how a rug is placed oddly in the room, that the cabinet sits with one door swinging in the wind, and the paint is flaking off the north wall.

  All of this has nothing to do with the story; it's just flavor. But by adding all these extra elements the players (1) think they are just as important as the treasure chest in the corner, (2) lock on to something besides the actual threat.

Another trick I've used is to overly describe something.

"You open the door and see a rather chaotic room. Although the room is unlit, there is some light coming from the moon outside the only window not boarded up. The floor is mostly carpeted, except in the center where it looks worn away. There are upturned tables and chairs pushed to the walls, emphasizing the clearing in the center of the room. Sitting in the center of the room is a large, wooden table, very different design than all the other furniture in the room. The light from the moon almost seems to spotlight the table. It has no chairs near it, nor any objects upon its surface. What do you do?"

Turns out the table is completely normal and was brought in there on purpose by thieves. They placed it there to make it very suspicious so that adventures would waste time and spells. However all the thieves are hiding behind the tables pushed against the wall (less likely to be hit by Area of Effect spells), and a couple that hide behind the now open door. When a few adventures do finally enter, they slam the doors shut, and lock the doors separating the party.

The key is to change up how you describe rooms. By drawing attention to mundane and downplaying important the characters will have to take their clues from something else.

The common theme throughout these types of the questions is that the DM will generally only call out things that are important. So if the DM says, "there are statues flanking the stairs," that must be important. Your description should not be on just the things the players need to interact with, but with what their focus would be. 

Describe how a rug is placed oddly in the room, that the cabinet sits with one door swinging in the wind, and the paint is flaking off the north wall. All of this has nothing to do with the story; it's just flavor.

"You open the door and see a rather chaotic room. Although the room is unlit, there is some light coming from the moon outside the only window not boarded up. The floor is mostly carpeted, except in the center where it looks worn away. There are upturned tables and chairs pushed to the walls, emphasizing the clearing in the center of the room. Sitting in the center of the room is a large, wooden table, very different design than all the other furniture in the room. The light from the moon almost seems to spotlight the table. It has no chairs near it, nor any objects upon its surface. What do you do?"

Turns out the table is completely normal and was brought in there on purpose by thieves. They placed it there to make it very suspicious so that adventures would waste time and spells. However all the thieves are hiding behind the tables pushed against the wall (less likely to be hit by Area of Effect spells), and a couple that hide behind the now open door. When a few adventures do finally enter, they slam the doors shut, and lock the doors separating the party.

Note how the description is keyed to the focus of the room. When the players enter the room, highlight what is obvious, and downplay the rest (mundane and threat alike). In my example, if you walked into a room with a single table, bathed in moonlight, with no furniture, not even the carpet within 10' of it, that is where the their perception will focus. I didn't NOT talk about the tables the thieves were hiding behind, but wouldn't be the perceived danger.

The key is to change up how you describe rooms. Drawing attention whatever is the focus of the room, and down play everything else.

"As you enter the ballroom, you are overwhelmed by the immense size. This grand room could fit the house you grew up in. Streamers litter the floor in a paper spiderweb. The chandeliers reflect the light from your torches across everything. The twinkling lights make it hard to focus. You can see a few dusty suits of armor to the south and north. There is a bar in the back where you can only imagine once held a buffet. Between the streamers, you can make out the tile floor a checkerboard of black and a light green; matching the drapes that cover the most of the walls. In the center you can make out what could be a dead body, partially covered by streamers."

Can you guess the threat?

It was the mimic disguised as the bar.