The Grisly Eye
Ric Wood's Blog
Encounter Blocks
Encounter blocks are an attempt to compress information about how to run encounters into a digestible format. This a preview of a as-yet untitled book on non-player characters I'm working on.
Here is an example of an encounter block for that common, low-level encounter, the wandering predators:

Header
As with the monster stat block, the header contains the name and a brief summary of the encounter:

I've used the level and threat
trap notation from Xanathar's Guide to Everything to describe rough tiers of difficulty. I intend encounters to be random with a range of possible challenge ratings. Hence the vaguer categorisation.
This needs some work to map the encounter difficulties from the DMG to encounter levels and threats. It might even make a better alternative to (much maligned) CR.
Attitude is a reference to the social interaction rules from chapter 8 of the Dungeon Master's Guide. I use these rules a lot in my own campaigns. Attitude also gives an important cue for how the encounter will respond to the party. Hostile encounters will generally be combat encounters. Isndifferent/friendly encounters would be some kind of non-combat challenge or roleplaying opportunity.
Description
After the header follows a description of what monsters/NPCs make-up the encounter. This is usually rolled for. For example:

This has a nice side-effect of grouping monsters and non-player characters under similar themes. Sometimes it not always obvious which monsters work well together.
Tactics
Next is the Tactic
section, which describes how to run the encounter:

This is the core of the encounter block: the Monster Manual doesn't always make it clear how to actually run monsters. The tactics section makes this explicit in an easy to consume format. A DM can look through the sub-headings here and quickly have a clear idea of how the encounter will react to the party and what it might do in combat.
Hat tip: Borrowed from u/kinseki on r/RPGcreation.
Habits
Last is the Habits
section:

Habits are the everyday things a group of monsters and NPCs might be doing when encountered. They serves two purposes: first, to help set the scene for the encounter. Is the wandering predator lying in wait to pounce, or looking after it's young when the PCs happen upon it?
It also helps with verisimilitude, encouraging a sense that the world is moving even when the party are not there. DMs can give the sense the party have stumbled onto the monster in media res. The encounter isn't waiting around for the party arrive like a computer game NPC.
Summary
I hope you found this useful, please feel free to steal any and all of the ideas here. All I ask is you let me know how you used them, and what did and did not work.