Rinse: Always rinse your glasses off with water before wiping or cleaning them.
Spray Carefully: If you're going to use a chemical, use sprays or cleansers that are specifically made to clean eyeglass lenses.
Air Dry: If you can, allow your glasses to air dry. This is another great way to keep any materials from getting on to your lens.
Use the Right Cloth: Never use paper towels, tissue, or napkins to dry your lenses. All of these materials, regardless of how soft they are on your skin, have a textured surface and can easily scratch your lenses.
Store your glasses when you're not wearing them. This isn't just a great way to keep dust and dirt away from your eyeglasses, but it also protects your specs from getting scratched, bent or broken.
Don't lay your glasses lens down. This is just asking for scratched lenses.
Washing your glasses at least once a day will keep your lenses in their optimal state. The cleaner your glasses, the less your eyes have to strain to see through smudges, dirt and dust.