Buy a package or jar of pure phosphorescent powder. You can get this from some craft stores or from an online supplier. The pigments come in different colors and particle sizes. Large glow-in-the-dark particles are more luminescent but yield coarser paint. Fine particles don't glow as strongly, but the paint will have a better consistency.
Buy some clear acrylic gel medium, polyurethane or epoxy. Thick matte gloss works best, but you can experiment with a high gloss medium and even iridescent gel.
In a disposable bowl, mix 3 to 4 teaspoons clear medium and 1 teaspoon glow-in-the-dark powder. If you have trouble getting the powder to incorporate into the medium, try adding a dab of white acrylic paint as a binder. Mix small batches at first until you figure out the perfect ratio of powder to medium. When you become confident that you have the right consistency, you can mix several different batches to have different colors.
Use the paint the same day you mix it. To make glow-in-the-dark accents last longer, apply the paint in several thin coats, letting the paint dry between applications. For a more professional look, try using stencils to spell out words or create designs.