Pour equal parts concrete acid stain and water in a garden sprayer with an adjustable nozzle. Close the lid and shake it up to mix. You need to be wearing gloves while you handle concrete stain.
Adjust the spray nozzle to a mist setting. Finer mists will coat the surface of the concrete with a smaller speckle so that it doesn't look splotchy.
Put on eye protection before spraying the coloring. You never know when there may be a breeze come through, and this is not something you want to get in your eyes.
Spray the concrete patio with the acid stain. Work your hand in a circular motion, not back and forth, trying not to go over the same area twice.
Rinse the stain out and fill again with a secondary color that compliments the first, such as shades of brown. Spray the concrete again with the new color.