Think of it like an elevator pitch; if you can express what your game is like, what it's about, and what characters are likely to do in the game, the better your chances of attracting players who will be interested in what you're throwing down. The keys to doing this well are threefold: present something that will be intriguing, memorable, and succinct. But I'm going to make it tougher: you don't get ten or eight items for your list. You only get five.
A useful exercise: can you express what your D&D campaign is about in only five lines?
Since I'm currently running two separate campaigns in two separate settings, I'm doing this twice:
- Gothic horror. Once a country of picturesque villages, deep forests, and sublime mountain ranges, Krevborna is now preyed upon by werebeasts, witches, malicious fey, fiends, and the undead.
- A hunter must hunt. As a player, your goal is to hunt monsters and fight back against the darkness that taints the land.
- A fallen monarchy. The hereditary royalty was overthrown generations ago. Farmsteads, villages, and towns are now independently governed. Chancel and Piskaro, the largest cities, are under the Church's control. There is no monarch, no standing army, no dominant power to protect the land and its people.
- The mark of evil. The mining town of Hemlock is ruled by a coven of Graymalk witches; in the cold, northern realm of Lamashtu, the populace pays a tithe of blood to the vampiric Countess Alcesta von Karlok. Fell influences tighten their grip across Krevborna.
- Blood-red religion. The Church of Saintly Blood venerates a cult of martyrs through rites that involve the imbibing of sanctified blood. It is the last bastion of authority in Krevborna, yet the Church is internally divided by factions, intrigue, and corruption.
- A megalodungeon. Scarabae is a city that spans five islands in the Ink Sea. It is so massive and complex that no accurate map exists of its entirety. Slithian Vor, a devil from the lower planes, is Lord Mayor; she receives council from the Courts of Swords, Coins, Cups, and Wands. (They oversee military, economic, religious, and magical affairs, respectively.)
- Cosmopolitan fantasy. The city's populace is an anarchic mix; the usual fantasy races—such as humans, elves, goblins, etc.—rub shoulders with otterfolk, minotaurs, genasi, and even stranger folk.
- Picaresque adventure. As a player, your goal is to explore the city's strange locales, acquire its valuable artifacts, interact with the intrigues and schemes of its odd denizens, and defeat ne'er-do-wells and monsters alike.
- A magical-industrial society. Magic is commonplace in Scarabae and often used to achieve marvels such as ethergram communication, mechanized factories, automatons, and conveyances such as worm trains, airships, and submarines.
- The Major Arcana. “Gods” are thought to be aspects or guises of the tarot's Major Arcana. It is believed that each Major Arcana represents a cosmic principle that shapes existence. The Major Arcana are opposed by the fiendish Maraphim.