I semi-consistently DM (dungeon master) one-shots and campaigns for my players. This involves a series of projects, both big and small, with the primary goal of building a world for my players to interact with. With the help of some rules established in Dungeons & Dragons 5e (fifth edition), I am able to create a story and experiences that my players and I can enjoy.
While there are many published D&D 5e adventures that I (or any DM for that matter) could run, it is almost never the case that the story you and your players create will fall within the confines of the book. Sure, it helps with a lot of world-building aspects like establishing environments and locations, NPCs (non-player characters), and story/plotlines, but all it takes is the wrong roll or swing of a sword to totally derail the adventure. Keeping the players feeling immersed is very difficult, especially when they enter a location or meet an NPC that doesn’t ACTUALLY exist (in writing, or anywhere). There is a consistent need for creativity, imagination, and ingenuity to keep the game going.
“Homebrew” is a term in D&D that refers to when you make your own rules, build your own world, or write your own adventure… or something to that extent, anyway. I have run a few homebrew adventures, and they require a slightly (very, very) different approach when it comes to worldbuilding (versus a prewritten adventure). This is because you have the benefit of total flexibility when it comes to the rules of your world. This can be helpful because there is no strict boundary on what can or can’t be done. On the other hand, it means that you need to have a rock-solid foundation to build your world on. - Where can the players go? How much does this item cost? How do these NPCs react to a certain action? - Homebrewing helped me build similar proficiencies as running a published adventure, as well as an elevated level of creativity and problem-solving, as there usually isn’t an immediate answer for what you want to do. It’s all up to you.
To give you an idea of some of the immersive qualities, here is an excerpt from a one-shot I built into D&D 5e:
The Sword Coast… A vast expanse of land in the Forgotten Realms where men, monsters, and races of every kind coexist. A place where an encounter with an Orc on the High Road to Neverwinter is chivalrous and ends with shaken hands. That’s not to say it’s all happiness and rainbows, though. At the heart of this slice of the forgotten realms lies Neverwinter Wood - a monster-infested shadow cast by the trees above. Fortunately, this adventure doesn't begin in the midst of such danger. To the south of Neverwinter Wood is a town called Phandalin. Shielded by the Sword Mountains and bisected by the Triboar Trail, Phandalin is home to a plethora of quiet, hard-working folk. Farmers, stonecutters, blacksmiths, traders, prospectors, and children alike occupy its stone and log houses. Our story begins here. Within this town, within an inn, inside of a room, a Tiefling wakes up to another sunrise. (Player), please introduce yourself.
If you’re interested in Dungeons & Dragons, this might help: How to Play D&D.