What should I do to have amazingly soft, silky hair and great skin?

Here's the thing. I've always had wavy hair. They used to be silky when I was young, but lately they have been coarse, oily and full of dandruff. So much that I had to get them cut really short because of too much hair fall, split ends and dull appearance. Most shampoos don't even suit me! Great hair add a lot to your looks and I really want them. I will start my college soon and the city I'm going to has pleasant weather. It rains a lot there. But the people who live there, who I know, tell me that the water is just not good for your hair. Or even the skin. What do I do? I'll be living in a hostel. I'll have Olive Oil with me (Figaro, not extra virgin). Could you recommend a routine for me? Also, what should I do to get an amazing skin tone and texture? Since, the schedule is very hectic, please tell me something which shouldn't take much time. Also, should I make some changes in my diet or habits?