On a weekly basis, take out the trays and other compartments and wash in warm soapy water, rinse and dry.  Clean the inside of your fridge using a solution of 2 teaspoons of bicarbonate of soda to a litre of warm water.  To clean the seals use a toothbrush and a solution of warm water and a little bleach.  Clean the outside too as well as the handle.  A couple of times a year pull your fridge out and vacuum the elements, this will make it work more efficiently too.