As you allow the Holy Spirit to lead you and to do His works through you, you are changed--transfigured actually, by the renewing of your mind that takes place during the process.  "Blessed are the pure in heart: for they shall see God." Matthew 5:8

It isn't sudden or dramatic but a little at a time... in the same way that little acts of rebellion and disobedience transform some people a little at a time, except that those people are becoming something terrible.

You reap what you sow.  Galatians 6:7-9  When the Holy Spirit does His work though you, you sow good seed. This seed begins to make your heart pure. As your heart becomes more pure, you begin to see Jesus more clearly and to hear His voice and understand His direction much better. The path of the just is as a shining light that shines more and more to the perfect [complete] day.  Proverbs 4:18