Decide what the guild is for
Every guild is for something: clearing raids, playing PvP together, telling stories, or simply having a friendly place to log in to. Trouble starts when the leadership thinks it is one thing and the members think it is another. Write a one-line motto and choose an atmosphere on your guild page, then run the guild according to them.
Say no to good ideas that do not fit. A relaxed social guild that suddenly starts tracking attendance because two officers want to progress faster will lose the members it was built for.
Write the rules, and keep them short
A guild needs a handful of rules that everyone can remember: how loot works, how raids are signed up for, how disagreements are handled, and what gets someone removed. If it takes more than a screen to read, nobody reads it.
Put the important parts on the About tab of your guild page and in a pinned Discord message. Applicants should be able to learn how you operate before they ever talk to a recruiter.
Delegate early, not when you are drowning
A Guild Master who does everything becomes the bottleneck for everything. Pick officers for recruitment, raid leading, the guild bank and the social side, and let them own those areas. The ranks on this site mirror that: officers can edit the page and review applications; recruiters can review applications without touching the rest.
Delegation also means letting people do things differently from how you would. If the outcome is fine, the method is fine.
Make decisions visible
Members forgive decisions they disagree with far more readily than decisions they did not see coming. When the loot system changes, when a raid night moves, when someone is removed, say so plainly and say why. Guild posts on your page and a Discord announcement channel are enough.
Do not run the guild from private messages. If a policy only exists in a conversation between two officers, it does not exist.
Handle conflict quickly and privately
Most conflicts are small and about one of three things: loot, attendance or tone on voice. Talk to the people involved directly and early, away from the raid. Listen first. Decide, communicate the decision, and move on.
When someone is harming the group, act. One person who makes raids unpleasant costs you several who quietly leave. If the conflict involves harassment, it is also a matter for the community guidelines, and you can report it here as well as handle it in the guild.
Watch for burnout, including your own
Leading a guild is a second job with no pay and a lot of pings. Take weeks off. Let an officer run a raid. Notice when a reliable member goes quiet, and ask how they are doing rather than why they missed a night.
Plan your own succession. Choose an officer who could take over, tell them, and use the Guild Master transfer on the roster page when the time comes. A guild that survives its founder stepping back is a guild that was led well.