In this video I shop, how you can make the drawing process a bit easier. All you need is a removable sticky label.
I stick it around the edges of the desired shape. This way I can simply dot around it. Great thing is, that ink doesn't bleed under the sticker. When you remove it, you have a clear and precise shape.
It is possible to use it also for circles or any other shapes. Just cut out the shape into the label and stick it on! :)