Like the person before me said the SpellCasters automatically accept people into the Council. Sometimes if a coven really likes you and thinks your worthy of being in the council they will accept your application into the council.
Most Covens put you into the members area first. This will see if your needed in the council. Being more positively active in your coven. Helping people, learning information on new subjects, teaching people, giving advice, and more are all things you can do. Council do help make decisions, so being open to learning things is always good.
I hoped this helped you a bit more! Blessed be )0(