Good solid advice from Distant Star. He's probably got a nicely evolved events workflow. There is a lot of great advice on this thread, much of which illustrates the diversity of how photographers approach events work.
I'd shoot a couple of events a week. FWIW here's a little on how I go about it.
The Brief: Get very clear communication from the client on what they want, how they're going to use it and when they need delivery of the job. I learned a long time ago not to accept a brief along the lines of..."well you're the expert, just do what you think is best...
" only to get feedback after the job is delivered..."well this actually isn't what we were wanting..."
Grrrrr. Insist on a written brief.
Cameras & Lenses: Always two bodies with Peak Design sling straps, 24-70 f/2.8II on one and 70-200 f/2.8isII on the other. Sometimes a third body with good high iso capability with a 24 f/1.4II. Typically the 24-70 gets used for posed shots, the 70-200 for candids. Two extra lenses that I'd keep nearby are a 16-35 just in case 24 isn't enough, and a 300 f/2.8is for some awesome candids, or required shots of speakers/presenters from a respectable distance.
Lighting: Speedlight 600ex-rt on each camera, plus additional lights depending on the job eg: a couple more off-camera 600ex-rt or Einsteins. With the on-camera flash, use bounce whenever possible, or if the room has high black ceilings, a diffuser such as a Gary Fong is great. I use Flash Diffuser Pro from Joe Demb http://www.dembflashproducts.com/
As we all know, straight flash looks pretty bad in most cases and should be used only as a last resort or for a particular look. For daylight fill, straight flash can look fine. Also, you can often make good extra money setting up a simple studio and asking the MC to make an appropriate announcement for you. People love it.
Batteries: I've had old 550 EZ speedlights explode when working them hard when powered by a Quantum Turbo. I had one go BANG two days after 9-11. Everyone hit the floor. Client was not impressed. Put in perspective, back in that time I was shooting 100 iso film and needed a ton of light, thus working the speedlights a LOT harder. Now my default iso at most events is 800 and on the 5D3 I have no qualms bumping up to 1600 and occasionally 3200 if that's what's needed to get the shot. Bounce flash at 1600 iso gives a great look, done well it looks like available light. I wouldn't walk out of the studio door without a fully charged Quantum T3 battery (with the twin outlets). Remote 600ex-rt are powered by the incredible value Godox Propac PB960 http://www.amazon.com/Godox-Propac-Battery-Output-Camera/dp/B00D06LUAA
(btw they come in black...)
Shooting: I tend to shoot heavily, frequently coming back from an event with 1500-2000 shots. Shooting a lot of candids, there is a high loss rate, but with a ruthless edit you really get those great moments that make the client swoon. In another life as a photo-editor for a metropolitan Sunday newspaper I learned to edit fast. If it's a maybe,
then it shouldn't make the cut. Another reason to shoot heavily can be to give an event a bit more sizzle. If you're doing your job well, communicating confidently and genuinely having fun, you're part of the entertainment. People respond to light energies, affinity, respect, humor and a bit of good natured nonsense. Like life, it's supposed to be enjoyable!
Invoicing: Be very careful about doing freebies or heavily discounted events. Better to be reassuringly expensive.