Mix equal parts white vinegar and water
Spray the solution onto the glass
Let it sit for a few minutes
Wipe with a microfiber cloth
Rinse with clean water
Dry with a lint-free cloth
Use a paste of baking soda and water for stubborn spots
Rub gently with a soft sponge
Rinse and dry again
Use lemon juice on light stains
Apply with a cloth, then wipe clean
Use a commercial glass cleaner if needed
Repeat as necessary
Prevent future stains by drying glass after use