Here are a few resources to help you with witnessing with tracts.

First – the Pocket Testament League has some wonderful resources for using just the Word of God to witness.  You can order Gospels of John to hand out.

Second – they have a good 7 lesson email “witnessing boot camp” to help you learn how to witness via their Gospels.

Third – they have a Facebook page.

Finally – consider ordering some Gospels of John to give away. They have them for all kinds of circumstances and themes to appeal to everyone from athletes to soldiers to surfers.