Witnessing Without Saying a Word
Generally speaking I notice it when people wear a cross somewhere (necklace, ear rings, etc).
The idea is that when people see the cross, they will start to think about God, and may even start a conversation with you about it.
So, I recently put a patch on my backpack, which I wear all the time.

- Etsy
You can also buy a cross pin.

- Amazon
Or, even something as simple as a button.

- Zazzle
Inexpensive, and good fun!