What should be the proper diet to overcome joint pains?

I have been suffering from joint pains and not able to understand its main reason. I have tried lot of medicines for this but nothing worked for too long. Then my doctor suggested me that I should pay more attention to my diet as one of the reasons to have pain in joints could be lack in nutritional supplements. I want to know that what is the proper diet for joint health and what else should I do to overcome the lack of nutrients in my daily diet?