Start Small
When starting out don't overwhelm yourself with trying to learn every single rule, class, race, monster, spell, and stat block in the game.
If you are new to the role of Dungeon Master, or even the game in general, there is no shame in taking a moment to look something up, ask a more
seasoned player, or even just winging it for the sake of the session's progression. If you are playing with your friends then everyone should be
accepting at the table and that they are all here for one common goal, to have fun.
Have a "Session Zero"
Session Zero is a colloquial term used for when everyone gets together and discusses the game and the table rules prior to the first session.
This is important for a variety of reasons due to the unique nature of every campaign and it's players. This allows the DM to establish any homebrew
mechanics they will use, discussion on what material and source books will be allowed and so on are good information to bring up before hand since it
offers transparency to the players of what they can do. This is also a good time to sit down and talk about if there are any behaviors, themes, and topics
that will be off-limits and also determining the party's overall dynamic as some groups allow Player-Versus-Player while others frown upon this type of play.
Utilize Your Resources!
There is absolutely no shame in running pre-made campaigns and taking inspiration from other forms of media when running your game. Did a group that you
watch on Twitch run a really interesting dungeon with unique traps? You should put them in your game for your players to navigate through and even add your own
personal spice to them. Did you think the scene in The Lord of the Rings where Gandalf is squaring up against the Balrog on the crumbling bridge was as cool as
I did? Well, that sounds like a really fun and interesting encounter to have to figure out for the players as they escape a dungeon. Utilizing and drawing inspiration
from others is really a tool every DM uses whether they want to admit it or not. There are sites, forums, and so much more that people love to share their ideas for others
like you and I to help make our games as fun as they can be.
Create Templates and Shortcuts
When you are prepping for a session it is unrealistic to be able to account for every scenario. One thing that many DMs find that helps keep a game going smoothly is
they will often create their own tables for NPCs that come up such as a shop keeper or traveling caravan merchants on the roads. You can make these as organized or random
as you like and often involve rolling a dice to determine the random NPC. For example you could have two seperate tables that determine the shop keeper, one that determines
their race and another that determines their personality. You could set up a table for the race by assigning a race to a number on a dice (d6 and d8 work well for this) and
then whichever dice you would like to use for their disposition. 1. Human, 2. Dwarf, 3. Elf, 4. Tiefling, 5. Halfling, 6. Gnome.