Apply a coat of primer and let it dry. Then apply a white base coat. Sand it lightly once the paint has dried. Remove the dust with a damp rag between layers.
For our table, we used four marble-like shades of paint. In separate containers, mix one part of each different color with one part water and one part latex glaze (each should be the consistency of heavy cream). Squiggle two of the paint color (we started off with the Jackson Tan and Valley Forge Brown) mixtures onto a small area, and then use parchment technique to soften them.
Next to the parchment area, add a vein for a realistic marble look by pulling the the two other paint color mixtures (we used Coyote Trail and Hasbrouck Brown) into a natural flowing line with a dry brush or cheesecloth. The marble won't look realistic if you see brush marks, so crosshatch over them with a dry brush so they're almost imperceptible.
To create depth in the marble, slowly dab a damp sea sponge over the parchment area to reactivate it, and then lightly crosshatch over the areas with a dry brush.
Repeat these two techniques (parchment and veining) until the entire piece is covered. Avoid overworking areas as they'll lack the clarity and luster of real marble.
Add more texture by applying paint directly to the sea sponge. Dab it where desired onto the piece, and then soften it with a dry brush as above.
Once satisfied with the finish, add varnish with a foam roller as directed for a durable finish.