You need to remove everything you can from the floor area you are going to refinish. Sofas, curtains, tables, rugs, etc. Another, often overlooked, important thing is to block as much of the airflow through the area as possible. While your finish is drying any airborne particles will stick and become part of the floor. Anything left in the area or those surrounding it should be properly protected while sanding. Dust covers and plastic blocking doorways are two of the best ways to accomplish this.
Before Sanding
You want to go over your floor and fill in any cracks or gaps in the wood. Use wood putty in visible areas and caulk along the baseline if necessary. If your floor was beneath carpeting, use diagonal pliers to remove any left over staples or remaining carpet padding. Then go around and sink any nails that may be sticking out as these can damage the sanding equipment.
Floor Sanding
You need to wear a dust mask and ear protection, sanding your floor might the noisiest, dustiest thing you ever do! You want to start your sander above the floor and gently lower it down. Be careful not to gouge your floor, it isn't hard to do. Just remember to be gentle and let the sander sort of float along the surface of the wood. Also make sure you never let the sander sit in one place on your floor, it will leave a swirl mark in seconds that will take you hours to remove.
Sand with the grain of the wood. Move forward and backward over each row so you get a nice even sanding. The first pass is your rough pass, now you need to change to a medium grit paper and go over the entire area a second time. Then go over the floor again looking for cracks, gaps and nails. Use putty and sink any nail heads you see.
Now you want to use a palm sander with a fine grit paper for your final sanding pass. Once finished, vacuum the whole area including the walls and ceiling. You need to remove all particles, dust, and anything else that can stick in the you wood finish. Now it's time to buff. Follow the grain in the wood and start in the middle of the room. After that your wood floor is ready to be stained, that's it.
