Determine whether there are vertical studs extending from foundation up to the floor. On exposed framing, use metal connectors to strengthen joints where beams and posts join. Use nails or lag screws to fasten connectors to exposed framing in such places as porches, patio covers, garages and basements. If possible, remove such items and substitute something lighter, particularly above beds. Guardrails across the front will help keep books and other objects from sliding off shelves.
Rails can be of wire or decorative metal.
Remove heavy objects from top. A piece of rubberized anti-slip rug mat trimmed to fit under the object won't keep it from tipping over but will help keep it from walking away. Close hooks by bending them shut with pliers or wrapping them with wire. If you are using heavy plant pots, consider changing to something lighter. Restrain large appliances such as refrigerators with a strap or hook, remembering that a degree of flexibility provides more stress resitance.