hello.. how to gain height?

You can gain the illusion of height with improved posture, built-up shoes, certain cuts of clothing, etc. But as far as gaining height, unless you have not finished growing (I just Googled and many taller-than-normal men did not stop growing until their mid-20s, but we are talking about men who were already at 6'3" at age 20 and reached 6'7" or so at 25), surgery would be the only option. Such surgery is costly and painful. Check out this link for details: http://abcnews.go.com/Health/york-man-grows-inches-surgery/story?id=15776730

Depending on how much extra weight you want to lose it is possible to "gain height". In reality it's the height you normally would be. As you lose weight your spine will straighten and your posture will improve, making it look like you have gotten taller. Short of surgery and high heels you're not going to get any taller than your genetics allow.