Power wash the existing concrete, being sure to remove loose pieces of debris (e.g., sticks, stones and leaves). The surface must be washed thoroughly to ensure proper adherence of the concrete repair mix.
Use duct tape or painter's tape to cover the existing joints or any decorative spots (e.g., a child's hand print or initials) so they will be preserved during the resurfacing process. Remember to remove the tape before the mix is set.
Buy concrete resurfacing mix at your local home improvement store. Purchase a specific color or add tint to match the existing concrete. Prepare the mix according to the manufacturer's specifications on the bag. Apply using a shovel or similar tool.
Smooth the concrete out with a trowel until the surface has a smooth, even texture. If you are resurfacing a large area, be sure to do one section at a time, because the concrete may set up too quickly and ruin the project.
As a finishing touch, run a broom over the surface before the concrete sets. This will add a skid-proof texture and aesthetic appeal.