Choose the proper color and type of paint for your project. If you're painting a specific design on the lawn, bright, water-soluble colors such as reds, blues and whites show up well. If you're covering up dead spots, a green lawn dye is the best choice.
Rake up dead grass and debris. Use a wide-toothed lawn rake and rake the entire yard to remove as much dead grass as possible.
Lay your stencils out on the grass to get a visual of the potential design. Place the stencils on the lawn, adjusting them as necessary. Push a lawn stake through each stencil to hold them in place as you paint.
Pour the grass paint into a garden sprayer and push the pump handle up and down to pressurize the sprayer. Push down on the trigger, moving the sprayer back and forth to evenly fill in each stencil. Allow the paint to dry for one hour before removing the stencil.
Coat the entire lawn if you're covering dry spots. Fill the sprayer with green lawn dye and spray the grass, moving the sprayer in a slow, sweeping motion to coat each blade. Add a second coat if necessary for even coverage.