One key method to increase the usability of your D&D adventure is to strip out anything that doesn't help the DM at the table. Consider the following room description from an old Dungeon magazine adventure (apologies for image quality). #dnd #ttrpg

Most of the information in that paragraph is useless to the DM. It doesn't matter what happened in the room over the preceding centuries, only what the PCs see now.

What's worse is that the author, in telling us interesting things about the past, doesn't tell us anything interesting about the current state. What sort of refuse? What sort of rusty equipment?

People can (and do) argue that the extra fluff is bonus material. But I would argue that extraneous material actively makes the adventure worse, because it makes it harder to find the relevant information, and also greatly increases preparation time.

Massively long backstories at the start of an adventure are another culprit here. Please - just tell me enough backstory to make the adventure coherent. If you have heaps of additional flavor info about the history of the empire or whatever, perhaps put it in an appendix.