Just as any friend, to be a friend of God you need to learn to care about what He cares about.
The best way to do this is to listen to Him. Pick up a bible today and read a parable from one of the Gospels. By better understanding His concerns you can gain insight to grow closer to Christ.
No one has greater love than this, to lay down one’s life for one’s friends. You are my friends if you do what I command you.