If we're pretty excited about introducing a friend of ours to someone, we might talk about it for awhile, telling our friend all about this new person and how great they are. But if we never got around to actually introducing them, our friend would get pretty tired of the same old stories. It's the relationship that is important, not the knowledge. Sure, this makes sense, but it gets pretty tricky when you start talking about God. The most significant way, I believe, is to model the relationship.
Christian mysticism is about spirit meeting spirit, and a bond being formed.
The most important task you can do as an ambassador for Christ, is to spend time hanging out with God yourself. Spending some time enjoying God's presence, aware that God is enjoying yours at the same time, will do more for those around you, than any words you could work up. If you have a sense of intimacy with Christ, you will be able to do more than just talk about God. Six years ago I made a commitment to spend one morning a week out at a retreat center for reading and meditation. It has become the center of my entire week.