Granite countertops

Granite needs very little care and keeps beautiful for years. Just keep it clean, wash it down after every meal preparation. Some granite may crack if a very hot pot is put on it. You can keep the shine for years if you do not use anything abrasive for clraning.

Unlike marble, granite is a relatively hard, non-porous, natural stone. It is relatively unaffected by most chemicals. However, I would not recommend harsh, caustic chemicals on it. Instead, I would clean your counters with a neutral, mild, vegetable oil-based cleaners such as our "Murphy's Oil Soap®." Synthetic scrubbing pads can be used on these surfaces. If any question arises as to what to use, test cleaning products on an inconspicuous area before cleaning visible areas.

Clean as often as needed keep grime and sand removed. Soil acts as an abrasive and damages the floor. Wet mop the solution onto the floor, and allow the solution to remain several minutes. Then mop up the dirt-filled solution, changing rinse water often. This helps to remove all soil and also does away with unsightly "mop lines." Keep the floor wet at all times during the cleaning operation. Otherwise, dissolved soil dries back onto the floor. When the floor is dry, buff with an electric polishing machine, if you have one. Buffing helps restore the natural sheen on the floor.

To remove stubborn soil, periodically use an electric scrubbing machine with a stronger solution of the neutral cleaner. Daily sweeping or dusting will mean easier weekly care and more attractive floors.

source:  http://www.doityourself.com/stry/granite 

Wipe up any spiliage

Wash down with non abrasive cleaner

Although granite can withstand heat try and place pans on a Hot Pad

Don't use it as a chopping board

Apply a sealant every couple of years 

Great answers by all of the above. Just want to add that I use granite Gold wipes. They seem to keep a nice shine on the counter tops.