Strengthen screw holes using a twist-tie.

Remove the loose screw, bend a twist-tie in half, and stick the bend corner into the hole. Cut it off with scissors, leaving a hole's-width sticking out. Bend the two protruding ends opposite one another, flush to the surface. Screw the screw in again — the thickness of the twist-tie will help keep the screw from pulling out.

Before putting your hands on bare wires, short them out first.

When you work on any in-wall electric circuits, shut off the power at the breaker. When you're absolutely sure the power is off, short out the wires using a screwdriver. If you have done everything correctly, nothing will happen; otherwise, a shower of sparks will indicate your error rather than you being electrocuted.

When working on an appliance, put the plug in your pocket.

Make a habit of putting the plug of any appliance you're working on into your pocket. That way, you'll be less likely to accidentally work on it when it's plugged in.

Wipe toilet seats with a small amount of toilet paper.

If you need to use any "unfamiliar" toilet (public or just at a someone's house) make a habit of grabbing a couple sheets of toilet paper first and wiping down the seat. That way you'll never sit on a wet seat and you'll know in advance that there is toilet paper.

Use used coffee grounds to wash grease from your hands.

Wash your hands with a mixture of a small pinch of used coffee grounds with ordinary dish soap to remove grease.