How to spend time effectively?

Learn something. Try learning from online tutorials which are useful; there are plenty of them (Photoshop, Joomla, HTML/CSS,...). It won't be useless if you know something extra!

you can read a book, with it is fictional novel like those of John Grisham or a self-improvement book like The Secret. Have fun

Well, you can go find a job to do. Like me, I'm also in the middle of a holiday and I'm now working at a shop, selling goods. By this, you will not only earn money for your savings but also give you an experience that may be useful in the future. Besides that, you can also go on a vacation. Spending some times with family and relatives. It's fun and relaxing. Well, these are the things that I'd done in my holiday. There are a lot of other things that you can do, you know.