Weight loss tips please?

im 6'1" and way around 240 mabie more. its not as much as it shows but its just not comfy and my stomach does stick out more than it should, i need advise on a good way i can lose weight, tighten my stomach and how to keep pounds off, i run the stairs 2-3 times everyday (about 12 flights of stairs and each flight has 9 stairs) and drink lots of water, any help please?