Smooth out or remove any bumpy, rough or loose areas on your ceramic piece with a putty knife.
Place your ceramic piece on a piece of plaster or a wood panel in order to catch any run-off glaze. Wood and plaster are particularly absorbent, so these materials tend to be best for this purpose.
Spray or paint on the glaze with a paintbrush, starting on the inside of the piece. Allow the inside area to dry completely after each coat. If you're painting on the glaze, try to paint in one continuous stroke, smoothing it out lightly by brushing back and forth. Apply the first coat horizontally, and then the next vertically. You can add a third, but you should follow the directions on your glaze container.
Spray or paint the outside of the ceramic piece, following the same method and number of coats as you did with the inside of the piece. If you spray too much, the glaze will drip off. If this is the case, scrape the excess glaze off with your putty knife, allow the glaze to dry completely, then apply another coat of glaze.
Allow the entire piece to dry completely. To highlight the high-gloss aspect of the glaze even more, you can apply a shimmery, glittery powder or paint and add another layer of glaze.