While there are many different products you can use to sand (a palm sander, a block, or sanding with paper in hand), the process is basically the same for all of them. Follow these steps, no matter the tool and you can sand like a pro.
Prepare the Surface First. Remove all tape or staples from the surface to be sanded. If necessary, scrape off blobs of plaster, paper, or flooring residue, glue, or any other material. Set all nails beneath the surface; one nail or staple can tear and ruin a fresh piece of sandpaper instantly.
Sand in Sequence. In smoothing a rough surface, you will need to use a sequence of two or three sandpapers, moving from coarse to fine. A medium-coarse paper of 80 to 100 grit might be an appropriate starting point for most sanding projects, followed by a finer paper in the 120 to 180 range to smooth the surface to the touch.
Protect Yourself. If you’re sanding old paint or plaster or sanding a great deal of anything, wear a mask or respirator. Some sanding dust is toxic; even when it isn’t, inhaling the dust is a choking, unpleasant sensation and potentially damaging to your lungs. Wet/dry sandpaper is an option, too, for limiting the amount of dust generated.
Clean the paper periodically. It will clog with dust, reducing its efficiency. Simply tapping the paper will cause most of the dust to fall free of the paper’s surface. That way, you can ensure all the elbow grease you used is actually making a difference on the surface.