Live event means no second takes. You must be ready and able to get it right the first time. Whatever is missed your going to have to do without.
This is why I get a clear indication from the event organizers of what they require or are mainly interested in showing with the footage. I can then organize myself and build a crew depending on the neads of the client. Some events simply need a multicam set up to achieve the required footage, while at other events you can get away with simply having a one man band.
So our main thing is preparation, not only as far as crew but also equipment. Will there be a need for audio will the job require mics, labs, recorders. All these are things that must be clear otherwise your lack of preparation will guarantee an unsatisfied client.
Be informed with the event you'll be covering having a little knowledge on what it is your covering will be beneficial in helping you make filming decisions, especially if your going to be the editor. Being smart on shot selection will make your life easier come edit time.
And mainly just be mindful of the clients needs. Deliver on their needs while adding your skills and expertise. These live events can be very hectic at times and it reflects stressfully on the client, so just be helpful and an asset to them.