I'd say consider the following:
Landmarks. Make the empty room a navigational aid. The big dragon skeleton. The three-headed demon statue. The really really smelly room. The room with "The Cake is a Lie" written on the wall. This is especially useful if you're doing a confusing OSR dungeon.
Foreshadowing. Use it to set up a later encounter. If there are trolls in the next room, add a big pile of troll dung. If there are ghosts, have the PCs hear chilling whispers from the dark. This is especially good for trick or puzzle monsters (trolls, medusas, undead, etc.) that can have devastating abilities but are much easier to deal with if you can prepare.
Ambiance. Use it to set add suspense, add backstory or interesting information, or just help players get a feel for this specific dungeon rather than some bland cookie-cutter thing. Exploring an elven tomb? Add bas relief sculptures of the deceased glorious deeds. Going into a dragon's lair? Show the massive footprints.
Usable features. Make the terrain in the room interesting and useful. An empty room split into an upper and lower section, separated by a 10 foot drop can be employed by a resourceful party. Or perhaps there's an obvious pit "trap", precarious (and heavy) statue, a one-way door, narrow passages or even something outlandish like a reverse gravity effect. All of these might be used to great effect against creatures in adjacent chambers if they can be lured in. Remember, tactics suggests using the terrain to your advantage. This is hard to do if the party is constantly forced to fight the monsters on their own terms. Give them interesting terrain options and get them thinking about how to maneuver baddies to their advantage.
Spacers. One of the most important aspects of empty rooms is as spacers. They slow down the craziness and add an important element of doubt in the mind of the players. If EVERY room has a monster, trick or trap than the players are on full alert at all times. If 1 in 3 rooms is "empty" and not dangerous at all, then they don't KNOW the demon statue is a trap. They just really suspect it. It makes a world of difference in pacing, suspense and overall engagement. As such you can present a few features that look like they might be dangers or treasures and have them, upon further investigation, be nothing.
Easy Challenges. I like to throw in extremely easy challenges for the party in some rooms. Puzzles with obvious solutions, dangers that aren't particularly dangerous, hazards that are easy to avoid or even enemies far below the party's level. These challenges should be easily assessed and quickly overcome, but they give players a burst of confidence, give the sense of advancement and, at the same time, add a certain verisimilitude to play as it's unrealistic to think all challenges faced by a party will be level-appropriate. For experienced characters it can be a reminder of how far they've come.