Fix floor damage
The methods or techniques for repairing floors will vary based on the type of flooring it is. Considering the abuse that a floor tolerates due to all the foot traffic it sees, it's a wonder that flooring and stairs last as long as they do. Depending on the type of flooring you have, you could be dealing with concrete floor repair, garage floor repair, hardwood floor repair, simulated wood or stone laminate floor repair.
Concrete Floor Repair
Concrete floor repair typically involves filling in small chips and cracks, and with few exceptions is fairly simple to perform. Smaller chips and cracks are basically a good thing in that they don't indicate any major problems with the actual structure of the concrete slab itself. It also means that the foundation doesn't have any problems either. However, as soon as these chips and cracks are noticed, they should be attended to so they don't have a chance to get worse.
The first thing you'll want to do is to take a stiff wire brush and clean the chip or crack out. Sweep up the debris and then vacuum over it. You can then seal the crack with some concrete crack sealant, available at most hardware stores. If by chance the crack is over a half-inch deep, you'll want to partially fill it with sand up to the half-inch level, and then fill it in with the sealant. Apply the sealant in quarter-inch layers until the crack is filled and level.
Hardwood Floor Repair
Hardwood floor repair is usually more time-consuming and definitely messier. If the floor is in bad shape, you're going to be sanding it down, re-staining it and then refinishing it. Sanding is usually done with an electric drum sander that has a catch-bag attached to it. When you sand the floor on the first pass, use 20-grit paper. Then repeat the process with 40-grit paper, and then with 100-grit paper the third time. This should remove any of the old finish.
You'll have to use a handheld sander around the edges, but you'll use the 20-, 40-, 100-grit routine that way as well. Once the sanding is finished, you'll need to perform a thorough clean up. If it's a pine floor, you'll want to use a pine sealant. If it's oak, apply a little turpentine to see if you'd like the floor unstained. If this doesn't appeal to you, then you're going to want to stain the floor to taste. Once the staining is complete, apply a couple of coats of clear polyurethane finish and the floor will look brand new.