Maybe your Discord server has more players than one table can hold, or your group hasn't agreed on a free evening since spring. West Marches handles both. There's a pool of players instead of a party, whoever is free plays, and they all share one world.
Most of the work comes before the first session. After that the players decide where to go, and the GMs mostly react. New to the term? Start with What is West Marches.
Do you have enough players?
West Marches needs a crowd. I'd say the smallest version that works is one GM and six or more players. With fewer, a normal campaign will suit you better. More GMs make it better still.
World and content
Home townOne safe town where every session starts and ends. No plot, and no NPC adventurers. Players should learn things by exploring, not by asking around at the bar.
Frontier regionsThree or more, each with its own creatures and hazards. The farther from town, the more dangerous.
Routes out of townLet mountains and rivers split the map into a few paths, so a new 1st level character can explore somewhere the last one didn't.
DungeonsMostly five-room dungeons that fit in one session, about three bigger ones, and maybe a megadungeon that links several. Cleared ones don't stay empty for long.
Treasure roomsA hidden room or a much harder fight, with the best loot. Players who can't crack one will keep talking about it.
CluesEvery site points to at least three others. Vague rumors get ignored, but a named sword in a named ruin gets a session booked.
Factions and villainsA few factions fighting over the wilds, and three villains whose plots move on whether the players get involved or not.
A shared mapOne map everyone can see, kept up to date by the GMs. Three-mile hexes work well. WestMarches.games has hex maps with fog of war you clear as groups explore.
Keep all of it in the World Wiki, with GM-only pages for the secrets.
Discord and scheduling
HandoutsRead-only for players. The rules, the books you allow and the house rules.
Table rulesCharacter creation, trading magic items, and how to book a session.
GM guidanceGMs only. Building encounters, how much loot to hand out, prepping a dungeon.
AdventuresA forum channel with one post per session. On WestMarches.games the bot writes these posts, with a button to sign up.
ChatAs many channels as you like for memes, map updates, logistics and war stories.
In the original West Marches the players scheduled every session. Most online communities flip that. GMs post adventures, and players sign up for the ones that fit their evening and time zone. WestMarches.games works that way too.
Session flow
Someone posts the adventure a few days ahead, with where the group is going. Six players at most.
The group sets out from town.
On the road, the players pick the route and the risks.
At the site, they explore and decide whether to push on or head back.
Everyone heads back to town if they can, so the next group can carry on.
The players write the recap, not the GM, who knows too much. On WestMarches.games the bot can post it under the adventure's Discord post.
Use XP, not milestones
Milestones make no sense when every session has a different group. Whose milestone was it? XP is earned per character, and on WestMarches.games it tracks itself. You set the XP for each level in Settings → Experience Ladder, the GM hands it out after a session, and the site levels the character. Watching the number go up is more fun, too.
Give XP for monsters defeated, and match each dungeon's treasure to its level.
Agree on loot per level, so no GM becomes the popular one by handing out more.
Reward more than items. Boons, titles and training work too.
Make it deadly
West Marches works best when it's dangerous. Mystic Arts counted three character deaths every four sessions in their campaign.
Roll in the open. It's the dire wolf that kills the party, not the GM.
Make threats visible, and always leave a way to retreat.
Let players keep more than one character. On WestMarches.games a dead character is marked Deceased and keeps their history.
Several GMs, one world
Write a GM guide covering encounters, loot per level, downtime and resurrection. A GM-only wiki page works.
When a dungeon is cleared or a villain dies, update the wiki straight away.
The adventure history shows every GM who went where and when.
Adventure attributes (your own fields, like region or danger) are a Patreon feature, and so are loot tables for handing out items quickly, from the Heroic tier.
The social side
Ben Robbins called this his biggest warning. West Marches is, in his words, "a swirling vortex of ambition and insecurity". Why did nobody answer when I asked for a group? Why wasn't I invited?
If cliques form, make parties mix after two adventures together.
Announce every adventure in the shared channel, even ones planned in DMs. The bot does it for every adventure posted on the site.
Let loot and trading drive the game between sessions. A marketplace helps.