Hobby/craft stores will have stencils for letters and numbers.
CIE is right. lightly sand w/200 grit to rough the surface, clean with Mineral Spirits and paint. A cover coat of polyurethane will seal it.
Don't use Shellac or Varnish, they chip much easier than poly.
Good luck, doesn't sound like you've done too much of this. Take your time and get it right the first time. Trying to clean up mistakes will take longer than just doing it right.