What is the best way to clean the keys and prevent dust from getting inside them?

Please try the following method:

1. Turn it upside down and shake it.
2. Use cotton swabs or a brush to get between the keys.
3. Use a small amount of isopropyl alcohol to remove persistent grime.
4. Use the compressed air spray to blow debris away.
5. Use a mini USB keyboard vacuum. (Note: please do not try to use a full-sized vacuum on a keyboard.)