Drywall is abrasive ... Once it’s dry, take the included sanding sponge, put on a dust mask, and sand it as flat as you can while leaving enough spackle to prevent the cloth scrim from showing ...

a package of 150-grit drywall sanding paper that's precut to fit your sander, and a sanding sponge for corners and detail sanding. You'll also need a double-strap dust mask rated for nuisance dust ...