The trick to stencilling is to use as little paint as possible, evenly distributed onto a stencil brush. Test by wiping the stencil brush on a piece of newspaper, if the stencil brush is wet you are using too much paint. Remove any excess paint onto a piece of newspaper. The dryer the brush the greater the success.

Secure the stencil using masking tape.  The masking tape secures the stencil but also allows a larger area to work on.

Move the stencil brush in a circular movement when applying it to the stencil. Holding the stencil down with your free hand.