Start at the top
Often when someone is leaving, it's natural to start by telling friends in the guild. But consider starting from the top and telling your guild leader first. It might be harder than just letting word get out, but if you're upfront and break the news to the guild leader first, chances are he'll be more understanding and even help explain things to the guild when they do catch wind of your departure. If there's one person who can diffuse drama it's the leader, so having him on your side is important.
"Hey everyone, I'm leaving!" might be the best way to spread the word about your departure, but it certainly lacks tact. Find a time when it's quiet (like, not the middle of a raid) and devote some time to talking with guild members and perhaps even answering questions if you feel it won't get too emotional. Tells are better than guild chat, because you can avoid the potential for the pile-on and the chance of drama.
Your input is appreciated
Honesty is the best policy, especially when it comes to leaving a guild. In that private discussion with your guild leader, be honest (but tactful) in explaining why you're moving on. It's extremely difficult to see through the emotions sometimes, but the reason for your departure is actually valuable feedback for the guild leader. Just as MMOs seek your replies to surveys when you unsubscribe, guild leaders can use your feedback in order to make adjustments that could prevent more potential departures. If you approach things in a rational and calm tone, you can hopefully convey those reasons and help the guild in the long run.
Leave it up to the leader on a time table
This usually doesn't happen, but if you're considering leaving, keep in mind the "two week notice" that we traditionally extend to our bosses in real-life jobs. It's certainly possible that the guild will want you to do a Marvin K. Mooney and please-go-now as soon as you express your intentions, but consider offering up your talents for a fixed time frame in order to help the guild transition and find a replacement.
If you're going to do this though, don't half-speed it. If you're sticking around for a lame duck session, continue to give it your all, and perhaps even 110%, because you don't want to look like you're phoning it in, and you do want to give the guild and your friends the best chance of continuing on after you've moved to another guild. I know you're itching to be a rock star in your new prospective guild, but factor in that transition time as a way to compensate the guild for your departure. You can walk away without regrets.
Don't take if you know you're going
Yes, you might deserve that awesome upgrade in a group or a raid, and you might deserve that rare spell or valuable crafting resource from the guild bank, but think twice and even three times about accepting it if you think you're moving on soon. It's not that it's wrong, it's just that it looks really bad. Even if you feel you earned it, there will be members who will see you as someone who took advantage of the guild to gear up and seek greener pastures. Those who have played MMOs for a while know that gear is made to be upgraded, and you'll replace whatever amazing item you've received, but the damage done to your reputation might linger long after.
Leave behind what you can to help the replacement
Your absence will leave a void in the guild, and they'll have to find a way to fill it somehow. Consider making that a little easier by leaving something behind. Maybe you have some helpful items that have been sitting around in your bank and would be useful. Maybe you can make one final donation of coin to help cover things like rent or expenses. But even if you aren't swimming in wealth, you could consider leaving behind any advice or tips that might make it easier for your replacement.
A nice thank you note
I used to joke with a guild mate any time someone left the guild, and we used to take bets on when we'd see the "I'm only a tell away" posts and messages. It always just seemed so trite and insincere. However, it is worth considering making some sort of final thank you to the guild as you depart. It's a nice way of leaving on a good note, and you never know if you might want to return. If you can find a way to leave the door open as you move on, it makes it easier to maintain friendships and even rejoin the guild if you end up regretting your decision.
There's no easy way to leave a guild, particularly if you've been there for a long time and have a major role in the guild's progress. But if you have decided to move on, it's best to do things as professionally and as politely as you can. Avoid getting sucked into finger pointing and the blame game, because if you're leaving for an understandable reason, members will eventually come around. Sometimes, there is no right or wrong, but if you can take the high road as much as possible, you'll be able to leave on the best of terms and hopefully with no hard feelings.
Do you have a guild problem that you just can't seem to resolve? Have a guild issue that you'd like to discuss? Every week, Karen Bryan takes on reader questions about guild management right here in The Guild Counsel column. She'll offer advice, give practical tips, and even provide a shoulder to lean on for those who are taking up the challenging task of running a guild.