Make the Template
Draw a pattern into a piece of plywood. Cut out the shape using a jigsaw. Then, sand the template to create smooth contours. The silver band surrounding the bit in this example of a plunge router is a template guide. With a template guide and a fluted bit, bear on a router template and cut a piece below the template easily. Make both inside and outside cuts with the template guide. They come in different sizes to accommodate the size of the bit. There is a slight offset of about 1/16 inch when using a template guide, so remember to compensate for the difference.