lol It's no secret
I learned it from a jewelry magazine a long time ago.
I wrap one end of wire around rounded pliers till the clipped end meets the wire making a circle. Then I move down 1/4 of an inch or less (depending on how close I want it) and bend the wire (turning it the opposite way of the first circle) around the round pliers. After I've made the second circle I cut off the wire where it meets to make the circle, and bend it to close it off. Does that make sense?