Summarize:

Any round object will work. You can use a round glass, the bottom of a candle, or a circular piece of paper. Just make sure the rounded edge is smooth. Take the round part of the object and place it flat on the paper where you want to draw your circle. Use the hand you don't draw with to hold it in place so it doesn't move when you're tracing it. Take a pencil and follow along the round edge of the object until you've completed the circle. When you're finished, take the object off the piece of paper and you'll have a perfect circle! If there are any gaps in the circle after you move the round object, fill them in with the pencil.
Find something round that you can trace. Hold the round object on a piece of paper. Trace around the edge of the object.