A screwdriver looks like a really simple tool. Perhaps that is why a lot of people have never bothered to master its correct usage. First of all, you should always choose a screwdriver of a length and tip fitted to the screw. Screwdrivers are specified by length of blade. The tip must be straight and virtually parallel-sided. It must also fit the screw slot and be not broader than the screw head. A tip that is too wide would scar the wood around the screw head. When the blade is too thin you might twist and break the tip, or if the tip is overly narrow, the screwdriver will ruin the slot. A driver that is not held in line with the screw would slip out of the slot and spoil both the screw and the work. And when the screwdriver tip is rounded or beveled, it will come up out of the slot, spoiling the screw head. When the tip is damaged, you can regrind or file it to make it straight.
Always use the longest screwdriver handy for the work. More power can be put on with a long screwdriver than with a short one, normally because the longer screwdriver has a larger diameter handle. Hold the handle securely in the palm of the right hand using the thumb and forefinger grasping the handle near the ferrule. Using the left hand (if you are right-handed) brace the tip and keep it pressing into the slot while renewing the grip on the handle for a new turn.
When no hole is bored for the threaded part of the screw, the wood is often split or the screw is twisted off. If a screw turns too hard, back it out and enlarge the hole. A little soap on the threads of the screw also makes it more comfortable to drive.
There is a regular procedure that is best used to secure two pieces of wood together with screws: (1) find the positions the screw holes. (2) Bore the first hole in the first piece wood slightly bigger than the diameter of the body under the screw head. (3) Bore the second hole slightly smaller than the threaded part of the screw. Bore as deep as half the length of the threaded part. (4) Countersink the first holes to match the diameter of the heads of the screws. (5) Drive the screws tightly in place using the screwdriver.