Day 24 - Acclaimed Advice
So, I will give my favorite pieces of advice for DMing.
For Interesting Combats - make your players focus on two things at once. Example, a big troll enemy that regens every time and a group of minions that are difficult to hit (such as swarms). If they ignore the troll, it regens. if they ignore the minions, they drain their own hit points.
For Game Prep - Prep scenarios, not plotlines. No prep survives contact with the players, do not assume what they players will or will not do within the story. Merely prep what the monsters/enemies intend to do.
Finally - Play other systems besides your favorite (D&D, Pathfinder, etc). You will learn tons about system agonstic game design by playing things outside of your comfort zone. Some of my favorite pieces of game design for use in D&D came from other games. Examples, Clocks (Blades in the Dark), Countdowns (Monster of the Week), Short Term / Long Term Goals (Warhammer Fantasy 4e), etc.
For advice from other people:
I've already mentioned Matt Colville, Professor DM and Deficient Master in a previous post so i'll highlight my other favorite source.
The Alexandrian is EXCELLENT and the book Justin Alexander recently published "So You Want to be a Game Master" is amazing.
Adversary Rosters changed my life.