What's the best way to make a stencil?

A couple of solutions.

One is a material, sold in art and craft stores called "frisket." It is a thin, self adhesive peel off plastic material that you can cut to shape, place on your canvas or other substrate and peel off and reposition if needed. The fact that it "sticks" to the canvas helps keep any over spray from creeping under the stencil.

But frisket is fairly fragile and can only be repositioned a limited number of times. As an alternative, you can purchase sheets of acrylic from which you can cut your stencils. In some cases, you can cut manilla folders and dividers for your stencils. In these cases, you can get some spray adhesive and lightly coat the back of the stencil before laying it down.

Make a stencil from a plastic comic-book protector/cover. They're pretty cheap and are durable. They're also just the right size for your purposes. Not only that, they're reusable.

Effective Cursive Writing AQ :- Nope Neither Used Nor Heard .

cut ur shape in plastic, cardboard, or paper. and cut the shape out

use solid metal