It is true that around 70% of height is based on genetics, but you can still implement some methods so that you can grow taller by inches :).
The two most important environmental factors for growing taller are: growth hormone and nutrition. Growth hormone controls your bodies growth, so by increasing these levels you can grow taller - it has been scientifically proven.
It is definitely worth increasing exercise and healthy food intake if you are keen to grow taller. Many people miss out on the extra inches due to the lack of discipline in good diet and exercise. The best time to capitalise on this is during the teen years, although resources like this argue that you can grow taller in adult years too.