A Dungeons and Dragons campaign is an incredible opportunity to tell a story. Unlike other games, Dungeons and Dragons has no predetermined plot or story arc. It's all up to you, the Dungeon Master (DM). That means you're responsible for creating characters, plotting out their adventures, and weaving your own epic tale of adventure. Crafting an epic story for your Dungeons and Dragons campaign can be a daunting task, but with a little bit of preparation and planning, you can create something truly memorable for your players.
Our best piece of advice? Plan ahead. Know roughly what you want the story to be, major plot points and how they resolve, and importantly, how all the pieces fit together. Decide on how long you want the campaign to last before you start playing. For example, if you know you'll be playing for two months straight every weeknight after school/work/whatever, then you and your players should plan accordingly so their characters don't outgrow their gear, meet unkillable monsters or level too fast!
When it comes to characters, make sure that each player has a role to play and that they have a stake in the game. Make them care! Your players will care more about their characters if they feel like they have a stake in what happens during the game sessions. If there are things going on outside of combat (and there should be), make sure that these things affect the characters directly at some point during the game so that they feel like there is more at stake than just killing monsters and taking loot from their corpses.
And finally, have backup plans ready when something goes wrong and you can keep moving forward without having to stop completely. Because things will go wrong. You could have set up a whole haunted carnival with plot hooks left, right and centre but maybe your players take the advice of the barkeep and bypass the carnival completely. Maybe you planned a session long boss battle, but a few well placed spells and lucky rolls in your players favour mean that it’s over in two rounds. Things are going to happen, and the story needs to keep moving.
A bonus note, and my personal favourite, spend some time thinking about the NPCs! Interacting with locals in the setting can be a wonderfully immersive experience for DM and players alike.