Sand the laminate kitchen countertops with coarse-grit sandpaper.
Clean the countertops thoroughly with warm soapy water to remove any dust created during the sanding process. Dry the countertops with a clean towel before you begin painting.
Apply one coat of alcohol-based primer to the countertops with a paint roller. The color of the primer is not important because you will cover it with another layer of paint.
Choose four colors for your faux granite effect and purchase these colors in satin or flat latex paints. One color is the base color and the other three colors are accent colors.
Paint the dry countertops with the paint tinted to the base color of your granite. If you need to apply a second coat of paint to completely cover the primer, do so when the first coat is dry.
Pour some of the paint tinted to your first accent color into a paint tray.
Dip a natural sea sponge into the paint and pat the sponge lightly onto the dry painted countertop. Continue to do this over the entire countertop to create a random pattern.
Repeat steps 6 and 7 with another accent color when the first accent color is dry. The countertop now has a base color with two different colors sponge-painted on top of it.
Pour a small amount of the third accent color into a paint tray and add an equal amount of water to create a thin glaze.
Dip a stiff-bristle paintbrush into the glaze and shake the paintbrush over the countertop to create a splattered effect with the glaze. This random application will help create a realistic granite appearance.
Apply three coats of oil-based polyurethane to the countertops with a paint roller when the glaze is completely dry. Let each coat of polyurethane dry according to the directions on the can, or for at least four hours, before you begin to apply the next.
Sand the dry polyurethane with extra-fine-grit sandpaper until it feels smooth.