I’ll give you an honest answer since you deseve one because you’ve been opening so many threads with so many questions;
Firstly, your knowledge needs to exceed the knowledge of majority of the posters, you need to be able to give fruitful, coherent answers to the questions people ask, difficult questions. Secondly, you need to be patient and never give in to emotion, you always need to keep your cool. Thirdly, you need to be able to dedicate a lot of your time, months and years.
Also a degree related to the section you moderate would be welcome. And knowledge...deep knowledge on the subject you moderate. Which section which you would like to moderate do you have in mind?