To be sure granite countertops stay in nice condition after a hard day's work, take a few minutes every evening to clear them of clutter and gently wipe them down. Usually a soft cloth or sponge with hot water will be enough, but for a little extra cleaning power, a specially formulated stone cleaner can be used. Look for eco-friendly or "green" cleaners, as these will be gentle yet still effective.
To clean a splatter, first remove the dried-on food with a razor blade. Then wet the surface with your usual granite cleaner, or this DIY, inexpensive, safe one: equal parts water and alcohol in a spray bottle. Gently scrape along the surface to remove any remaining dirt. Use a soft sponge to wipe, then buff dry to a shine with a soft cloth.
Do not clean granite with acidic ingredients such vinegar, lemon juice, or lime juice, as they can be abrasive, and avoid obviously abrasive products such as scrubs and steel wool pads. Also avoid cleaning products that contain bleach, degreasing substances, or ammonia. Dish soap should be used sparingly, because it eventually will dull the countertop appearance.
Avoid dropping hard items on granite countertops, as the countertop may nick or chip. And while you can place a hot pot or pan on granite, try to avoid doing so, as it may leave a mark.
Granite countertops should be sealed biannually for more protection. The Marble Institute of America is a good source for all things stone.