Always wear safety glasses, even if you are not using any tools yourself, as chips and debris can fly considerable distances. Prescription eyeglasses are rated as safety glasses, and may be used as such, but remember that they do not protect from the sides unless you add side shields.
Take off all jewelry, roll up your sleeves and tie back your hair; do not give the machines something to grab hold of.
Learn where the following things are: Exits, fire extinguishers, first aid kits, electrical switchboxes and cutoff valves. Learn the use of each.
Never interrupt or distract anyone using power tools, unless you see a safety hazard that the person does not see. If you must get someone’s attention, move into their field of vision and wait for them to notice you.
Inspect any tool or piece of equipment before using it; if there seems to be anything wrong with it, do not use it, and bring it to the attention of someone in charge of maintenance.
Always ensure that the cutting tools you use are as sharp as possible; this includes sandpaper, which can get clogged or the abrasive dulled with use. The more dull a tool is, the more energy must be used to get it to cut at all, leaving less energy available for control.
Always remember: What a tool can do to wood or metal, it can do to your fingers, and usually more easily. Follow ALL safety rules, and use ALL safety devices.
Though “Do as I say; not as I do” is a Bad Idea generally, if someone is experienced with a tool or process and is over 18, you may see them taking shortcuts that are potentially hazardous. This is still a Bad Idea generally, though experience can substitute for safety devices. But that experience has to be there; if you just got your Learner’s Permit, you would probably not be able to safely drive to San Francisco, which any experienced driver could do. And if you’re under 18, you MUST use ALL relevant safety devices, experience or no.
Whenever possible, trip high-capacity electrical switches (i.e., in a switchbox), and plug in and unplug power cords, with your right hand while standing on your right foot. This will prevent possible electrical current from an electrical fault from flowing through your body across your heart.
Always inspect electrical cords (both power cords attached to equipment and extension cords) before use. If the outer casing is damaged but the wire insulation is intact, wrap the casing in electrical tape before using, and bring it to the attention of someone in charge of maintenance. If wire insulation is damaged, and most especially if conductor is visible, DO NOT USE IT!
Unplug power cords by pulling on the plug, not by pulling on the cord. Pulling on the cord can pull it right out of the plug.
If you must use an extension cord, use the shortest and largest-gauge extension cord available. If you have to choose, go for largest-gauge over shortest (remember: wire thickness goes UP as the gauge number goes DOWN – 8 gauge wire is thicker than 10 gauge wire).
If a power or extension cord becomes hot to the touch, TURN THE MACHINE OFF IMMEDIATELY! If necessary, turn off the power at the switchbox. Then unplug it if you can do so safely.
Never use anything that uses line electricity if the floor is wet (this does not apply to battery-powered tools).
READ THE MANUAL before trying to operate any unfamiliar power tool; even if it is a sort you have used before, reading the manual will tell you if there is anything unusual about this particular model. The manual is the best source for how to avoid hurting yourself.
Before turning a power tool on, check to make sure all retaining and adjustment screws/nuts are tight, all locks are unlocked, and all chuck keys or other adjustment tools are removed. Make sure nothing will be in contact with the cutting tool, especially your fingers.
After turning off a power tool, wait for it to come to a complete stop before making any adjustments or leaving it unattended.
Try to keep your body parts out of the plane of rotation of a power tool. I have seen an abrasive wheel explode and throw fragments 30 feet, and I have seen a 2X4, fed the wrong way into a table saw, thrown 10 feet to make a half-inch-deep hole in a cinderblock wall.
Whenever possible, brace the power tool against something other than yourself; this makes controlling it much easier and less tiring. The closer the brace is to the workpiece, the better.