When I created the GPH series of adventures, I had in mind to create four modules that are easy for a DM to just pick up and run.

Here is an excerpt from one of the modules:

GPH1: Alabaster Palace of the Earth Genies, p. 8-9

From this excerpt, I note the following:

1. One location entry per page or two.
2. Location number and name at the top of the entry.
3. Brief location description that can be read aloud to players.
4. Occupants of the location, including full stat blocks and XP value.
5. Other relevant details of the location, including treasure.
6. Mini-map and expanded map location.

For the layout, I decided on one or two pages per dungeon location. Two page dungeon locations are presented as a 2-page spread so that the DM would not need to flip pages to read the whole entry. Everything is visible at a glance.

Map locations are numbered and named in the heading at the top of the page. Headings and subheadings are distinct from other text so that the DM can see at a glance all the information categories for this location.

Location descriptions can be helpful for a DM who would otherwise have to make up on the spot what the PCs see. They are not more than a paragraph; too much information at once and the players may forget details.

The occupants of the location and all of their relevant statistics are listed. This saves time for the DM because he does not need to flip through the monster manual, sometimes for multiple different monsters in a single location.

For other details, I try to picture myself in the location and look around in my mind and think like a PC. Can I climb up to that window? Is the door locked? What happens when I ring that bell? While all of the possibilities cannot be listed, at least the most important details are covered.

For each entry, I have also included a mini-map of the dungeon so that the DM does not need to flip to a different page to see where the PCs are in relation to the rest of the map. Also the expanded map helps with smaller details that might not be as apparent from the original map of the whole dungeon (furniture, traps, obstacles, etc.)

All of these together make the GPH modules easy for a DM to pick up and run.