Getting the People to Get the Job Done Back
At some point in the planning of every convention, the conrunner realizes that they can't do all the work. Some of the tasks will have to be performed by other people. This is where many conventions run into trouble. Lots of people don't have experience in organizing people, so it's easy to make mistakes. But fandom is about people, and people are the most important resource for any convention. Conrunning is a management task, and one definition of management is "getting work done through other people." Fortunately, the time frame is short and the number of variables is small, compared to a business environment; you only have to survive the weekend. I have a simple approach in organizing fannish volunteers:

Finding People

This article is not about how to bring people into fandom. We'll just assume that future volunteers are current fans, the people you meet at your con or other conventions. The first point in getting people to work for you is to ask them. Some have trouble with this. One might assume that people will come forward, and a few will, but fans may be shy, or not sure they're welcome, or not sure the con needs more people. Others are reluctant to talk to people, thinking somehow it will just happen. It doesn't just happen. You have to get into the habit of asking people to volunteer. It helps to travel to nearby or related cons. After you've talked to a dozen people, it gets easier.
Another key is to answer email. Have a prominent page on your web site asking people to volunteer. If you respond within a week, people will think you're on the ball. If you respond within a month, they'll think you're a bit disorganized, but they'll still be happy to help. If it takes a year to respond (and this has happened with more than one Worldcon), people will be surprised when you contact them, likely committed elsewhere, and if they do volunteer, they'll feel like an afterthought, not part of the team, so if a crisis hits, they will have a "not my problem" attitude. The first email can be a "thanks for writing, we'll get back to you," though you should give people a time frame when to expect your next message.
The last key to bringing people onto the team is, when they offer to help, give them something to do. Don't leave people in limbo, don't make them "staff" without a more specific title. Once you give someone a title, they start to own it; the rsponsibility for success becomes theirs, and they start thinking of creative solutions.

Make People Happy

Here's a trick that I use: "This department is an elite team. We are specially chosen to complete this task, and the entire convention would fail without us. The work we do has been set up in such an optimized way that even if people watch us, they can't understand what we are getting done, or how much." Make it clear to the team that the department and task is important, and that the work they are doing will make a difference in the success or failure of the entire convention.
It's actually easy to make this true. There are a lot of critical teams within a convention, any one of which is necessary to the success of the event. Think of registration, programming, tech, facilities, everyone has a role to play. So all you have to do is explain how important the job they are doing is, and as much as you can, share any techniques or methods that can make your team more effective. But once you get this across, people will move with a lift in their step, they'll smile a bit more to external parties, they'll hustle when speed is important. Get them in the habit, and you can sustain an adrenaline level throughout the weekend. Not only will this help get a lot done, if your staff works twice as hard, it's as good as having twice as many people, and they'll also have more fun. That's essential. Because in the long run, the people who will end up working your con are not so much the people that you talk to, it is the people that your team talks to.
You might be thinking that the con chair can't say that every department isn't more special than every other. But they can. It goes something like this: "This convention is a unique event in the history of our organization. We are going to have <some special event> <some new tradition> <some special outside attention> <something we've never done before>..." After all, if you're running a convention, it should be something special. Give it something that hasn't been done before. Not only will the special event probably be worthwhile, but the extra mileage you will get out of the committee will definitely make the convention memorable.
The next point in organizing people is to delegate work to them. Sounds obvious, but again this is something so many conrunners miss. Delegation has four components: trust, monitor, advise, and help. Trusting people may seem hard, but without it, they are just reluctant puppets, and it is as much work to supervise them as it is to do the work yourself. You have to set them to a task, and then let them do it. It may seem contradictory, but monitoring people is also key. That doesn't mean watching them work. It means that you give them a specified task, and then when they are supposed to be done, check on them and see how it went. For volunteers who need a lot of guidance, you would have a very short cycle of delegation and monitoring, but the basic principle applies. If someone does good work, you thank them and praise them; if they have a problem, you redirect them. Which comes to the next point. If someone doesn't know how to proceed, or if they aren't performing according to your expectations, give them suggestions as to how they might get things done more effectively. Finally, if someone is unable to complete a task you've given them, you help them. Maybe they need a computer, or someone to lift and carry, or transportation somewhere. You can assign extra people to the job, especially if the job actually does need more hands. If you have to, you can assign a person to a different task, or you can give them a break, or you can just show them how to do what you want. There is almost always a positive way to do this, and almost never a need or an advantage to having a negative approach to volunteers. In the end, remember, the con will be over soon, and while maybe you can fix problems that arise (and problems will always arise), you can't change the past. Even the most incompetent volunteer may have friends and contacts; if you let them exit while saving face, they'll at least talk about how nice you were, or how cool you were, whereas if you fire someone at-con, they go back to whatever club they're involved with and they'll turn a lot of other people off your next con.
Another thing that is very important is communication, not just with the volunteers, but between them. The elements of communication are: listening, explaining, and having open channels. Listening is a basic technique in any leadership, service, counselling, or sales job, so maybe you've had some training. An important point about listening are to try to talk less than 20% of the conversation. Also, you need to be able to say what the other person is saying; summarizing it back to them to make sure you've got it is a good idea. The next technique is to explain things clearly. As best you can, outline in detail what you want them to do. Also, if there is doubt about the reason for an objective, one method of explanation that I use is something called "reverse empathy". All this means is that I explain my reasoning process for coming to a conclusion, leading them to the same result that I came to. Once they understand and agree that I have chosen the best option from what I have available, they are more likely to align their actions to my goals. The last element of communication is to have an open forum, where people can feel they have the opportunity to participate and contribute their ideas. Use a mailing list, a club meeting, whatever works. Don't try to dominate the discussion; the best ideas are the ones you haven't thought of yet.
Everyone remembers that knowledge is power. Some people use this to maintain a position within an organization, but in truth one of the worst approaches to leadership is to not share information you have. Some of the most effective leaders act like they know very little, that they rely completely on their team to know how to resolve a problem. That's a technique that can work well. Expertise can be a benefit, but this is a completely different thing from mere knowledge. Expertise is the ability to answer a hundred questions on a topic, to show people new skills and solutions over and over, and still be known to have more to offer. This does lend a person credibility and authority, but only by sharing knowledge, not by hoarding it. Expertise can make a person reliable, even indispensable, in an organization, but even then, a specialized area of skill is almost always unrelated to the ability to manage people. Remember that management is getting work done through other people, so your knowledge of how to get things done doesn't help, except to the extent that you give that knowledge away. This is one of the main reasons that communication is essential; people need to know that they can ask questions and trust that they will be answered.
The last aspect in making people happy, and the most important thing, is to acknowledge the work they are doing. Get in the habit of saying thank you for every little thing, in person and in email. Singling out people in large gatherings works really well. One of the most effective ways of acknowledging people I ever saw was the way Tom Whitmore had teams of people stand up during the opening ceremonies at ConJose, not just a few individuals. He ended this saying "everyone who doesn't know which division they're in, please stand up now," and that group was as numerous as any of the divisions. Nobody felt left out; everyone knew that they would be seen and recognized by those they'd worked with. Another very effective tool is any kind of personalized gift or written communication. Hand-written thank-you notes have a tremendous impact. At work, I gave a department Christmas cards with a personal note and a $5 gift certificate for books. Months later, I still saw those cards standing up on people's desks. Fans react the same way, only more so, because your gift or note isn't just a thank you, is a memento of the event, an item of fannish memorabilia. Group acknowledgement only works if you have a large audience; something personal, one person to one person, always goes over well.

Don't Piss People Off

These are just some observations of things that have spectacularly not worked over the years:

Final Thoughts

A good leader doesn't rely on their title, and doesn't just organize their subordinates. One can coach colleagues, superiors, even competitors. But if you're going to work with people and accomplish things through them, you will be much more effective if you care about them. This is a matter of worldview, not just technique; sincerity is essential. Similarly, to be able to do a job well, you have to be able to care about the job. You can't persuade anyone to believe in something you aren't committed to yourself.
The point of this entire piece is that you are planning how to run an event. People are a very important part of the plan, but not the only part. If you want to avoid a disaster, rehearse it. Having people around, having extra people around, is a very effective way to be able to react, proactively and reactively, to whatever situation may arise. The extra staff are "in training for next year," and you can always give them a sort of battlefield promotion if the need arises.
Have fun. Not just because that should be the objective, but for sure nobody is going to want to follow you unless you're in a good place. Besides, you're in this for a reason, just embrace your own motives. Share your enthusiasm. Remember that what you get from most people will be what you give them, so anything positive you contribute will be repaid many times over. If your organization or convention is worth doing, you won't be the only one doing it. Have a great con!