When sanding small objects, attach the sandpaper to a flat surface and then run the object that needs sanding over the paper. After sanding wood, pull an old nylon stocking over your hand and rub the wood lightly. You will be able to locate the slightest rough spots. Apply soap or wax on screws for easier screwing. As you need more wax, just turn the knob.
Longer screwdrivers have more leverage.
If a screw is loose, stick a wooden kitchen match or tooth pick in the hole and break it off, then put the screw back in. You can also wind a few strands of steel wool around the threads of the screw before screwing it in to keep it tight. For a wobbly drawer knob, paint the screw with fingernail polish before inserting it. On home appliances, for screws that keep coming loose, dab shellac under the heads before tightening them, this will hold them tightly in place. Store separated nails, screws, bolts, etc. in baby food jars.