i could tell you a cheesy step-by-step plan and give you specific pick up lines. But i won't. Because being a good flirt is not exactly like that. Don't ever say or do something that you're not totally comfortable doing. The best flirting is done naturally.
To be able to feel naturally flirtier, work on your self confidence first. Also try to feel more comfortable around other people, especially guys. It is not something you can easily learn. It takes time.
But you have all the time in the world, so why rush? Once you get a bf, things will be totally different. After my first boyfriend, i felt sooooooo much more comfortable with guys.
Oh... Best way to become a good flirt is to practice

. I found that it is easier to flirt with guys you don't know, especially when you are on vacation somewhere. If you don't know the guy, what have you got to lose?