We grow in the Spirit as we grow in Christian maturity. You grow in Christian maturity by regular church attendance, regular Bible reading, regular prayer, and by growing in obedience.
People that are Spirit filled are godly people. You can't be an ungodly person yet be someone that the Spirit uses.
Real Christian maturity takes decades. And it usually involves a lot of difficulties.
RE: Pursue God's Mission by the Power of the Holy Spirit