I'm sure you'll find this Tripp and Tyler video amusingly familiar (albeit exaggerated).
What can you do to make sure your conference call doesn't go as disastrously as this IRL (In Real Life) conference went?
Take Charge and Be On Time. Someone has to direct a conference call, just as with any meeting. It doesn't have to be the boss, but everyone needs someone who will decide who has the floor, whose turn it is to talk, and what the subject is. This person should also be first on the call, so that joiners are greeted, the clock (see below) can be started, etc. If the meeting moderator does not arrive on time, everyone else is stuck with music until (s)he shows up. It might also be good for the group if the greeter role changes hands as each new person comes onto the call. Make sure everyone agrees on the length of the meeting, and adjust the time or agenda if someone has to leave early. Here's a humorous take on what happens when someone joins a conference call after the meeting has been going for a while.
Who Are You? When you speak, identify yourself. This looks silly in real life, but - especially when conference calls are starting out - it's important to know who's doing the talking when you can't see them. And if you haven't spoken for a while, listeners may find it difficult to recognize you.
Noise. Close your door. Put your rustling papers out of reach. Don't move the phone, and put your pen down if you're a pen-tapper. Make sure your keyboard is quiet (if you insist on typing while Conferring). Take a cough drop if you're prone to hacking. That takes care of you, but how do you control those noisy participants calling in from airports, cars, or nursery rooms? The same way: insist that they either mute themselves or move to a quieter environment. In some cases, it's best to ask the caller to hang up and try again from a quieter phone. To avoid unnecessary embarrassment, ask callers to avoid cell phones and cheap speakerphones: they "buzz" or produce static that annoys everyone else, and their signals are prone to dropping. Also, make sure everyone knows NOT to put their phones on hold: doing so may result in unwanted music that will tempt everyone to regret that dental appointment they could have been attending.
Don't Interrupt. It's rude, for one thing. For another, it's very hard on call participants to understand what's going on when several people are speaking at once.
Call on People. Instead of asking if anyone has an opinion - which will lead to several people speaking at once - call on each person individually. You can do this with a single sentence: "I'd like to hear from Phill, then Michelle and then Chris." Also, don't let any one person speak longer than 10 minutes. Attentiveness and listening become compromised when the same voice dominates, and your group members will begin to multi-task (read e-mails, respond to IMs, make grocery lists) as you let this continue. Some moderators use the "Clock" method for directing discussions: the first person is one o'clock, second is two o'clock, etc.
Stay on Track. As with any meeting, a conference call needs an agenda and the call will be successful only if you stick to it. If all participants have a copy of the agenda prior to its start, you'll find it easier to bring them back to it when they begin to stray (and it will skirt the problem of people trying to listen and read at the same time). It's a good idea to prime the conversation by letting participants know in advance what question(s) you hope to have answered when you meet. Another helpful accessory - if you have time to prepare it and send it to participants - is a brief bio of each participant, so that everyone will know something about the person who's talking. If there are any pre-conference call tasks you need them to do or materials you want them to have for the call, make that clear in your invitation (boldface, ALL CAPS, etc.).
Grin and Bear It. Smile. No matter what. You sound better when you're smiling, and everyone will feel better because your voice comes across as friendly and happy.