Always try to remove your glasses with both hands.
Avoid placing your glasses face down on the lenses.
Avoid exposure to abrasive or solvent based substances and extreme temperatures (shower, car dashboard).
Only use a recommended cleaning spray and microfibre cloth to clean your lenses.
Bring your glasses in for tightening of screws should they start to wiggle loose.
Avoid placing your glasses on your head to minimise any temple splay.
Keep a case handy so you can store them safely when not using them.
To avoid problems always get the professionals (us) to carry out adjustments and repairs.