Being close to God is a very interesting proposition. Cynics may believe you cannot form a close relationship with an invisible spirit creature, but just the opposite is true.
God reveals himself to be a caring Father to his human creation. Just like any loving father, God wants to have a close relationship with us as individuals. He repeatedly guides us toward him by means of his inspired word, The Bible. (2 Timothy 3:16,17)
For example, a quote from James 4:8 reads in part, "Draw close to God and he will draw close to you." So we can be close to God by drawing to him.
To draw close to HIM, Jesus taught that we need to pray to God, and to live not by bread alone, but by every utterance coming forth through his mouth. (Matthew 4:4) God's utterances are in the Bible.
So along with PRAYING TO GOD, we must READ AND MEDITATE on what the Bible says, which should make us ready to OBEY his teachings and listen to him.
Once we reach out to God in these acceptable ways, God will draw close to us in return. Knowledge about him is just the start and the knowledge has to come from his recognized source of communication with humankind - The Bible. These are the primary reasons I feel close to God.