Quizmastering
First, read through the Resources and Checklists for Answer Judges and Quizmasters document. This covers software, equipment, basic how-to's, troubleshooting, preferred terminology and more.
Time
Quizmastering does not have to involve a serious time commitment, outside of attending the meets. However, most quizmasters do devote a lot of their time.
Questions
I have found the way to get great questions is to write them yourself, incorporate many other lists, and constantly seek feedback from other experienced and trusted question writers. I continually find invalid or substandard questions in my sets, even late in the year. That shows how important it is to constantly review them. Using Microsoft Excel, I can check for spelling, questions that start or end similarly (may be duplicates), super long questions (want to avoid for INTs and MAs), super long questions (also want to avoid for SITs and FT2Vs and QTs).
During a Quiz
Quizmasters have a large amount of responsibility during a quiz meet. They must keep quizzes moving, so that the entire meet stays on schedule. This requires discipline by the quizmaster. They must rule quickly, consistently, and decisively, to bring transparency and reduce potential contentions. The quizmaster must be very familiar with the rules.
Quizmasters must be able to read at a consistent cadence on every single question. Quizmasters must be able to stop reading very quickly after a quizzer jumps. Timing is very important to the quizzer. The quizmaster must be able to read all questions at a consistent pace, and stop reading consistently when a jump is made. Consistent pace of reading includes more than just the question; it includes the lead up and any pauses between phrases. Everything needs to be equal and consistent.