Clean the concrete with a pressure washer. If you don't have a washer, rent one from a tool rental store. Pressure washer wands have tips that can be changed to increase the pressure of the spray. Use the green or yellow tip to prevent concrete damage.
Remove any loose concrete that may remain in cracks or holes with a masonry chisel and hammer. Sweep out other remaining debris with a stiff-bristled brush. Wash out cracks and holes with a water hose.
Patch and repair holes and cracks with premixed concrete patch. Premixed concrete patch can be purchased from most hardware stores. This product is made with latex additives, which will help keep the concrete flexible and prevent cracking and flaking.
Clean grease spots with degreaser and a stiff bristled brush. Spray on the degreaser and allow it to set for 10 minutes. Scrub the degreaser into the grease spot. Wash away the remaining product with a water hose or pressure washer. Repeat the process if necessary to fully remove the grease.
Allow the concrete to fully dry before proceeding. Apply a bonding agent, found at hardware stores, along with the concrete topcoat. Pour the bonding chemical directly onto the concrete, beginning in the center and working out. Distribute the bonding agent with a paint roller.
Allow the bonding agent to fully dry to the touch. Pour out the concrete topcoat directly from the container -- a 5-gallon bucket -- and onto the concrete. Begin in the center of the concrete and distribute the topcoat with a squeegee. Apply no pressure onto the topcoat with the squeegee. Allow only the weight of the squeegee to press onto the topcoat.
Apply two to three coats, allowing sufficient drying time between coats. Observe the topcoat application instructions for proper drying and recoating times. Once the topcoat has dried to the touch, cover the concrete surface with plastic to prevent rapid drying of the surface. Allow the topcoat to set for 24 to 48 hours before applying heavy traffic to the area.