I was wondering what you guys think is the best way to tell a girl you are interested? Just a random question

Honestly and simply. Thats all there is to it. It all depends on the girl, but I doubt any girl, or anyone for that matter, likes reading between the lines. Just tell her youre interested. If shes into you, then shes into you. If shes not, then shes not. How you put it or how you word it will not matter if shes into you or not. Honesty is your friend right now.

Im a girl, and I have a lot of friends who talk about guys who confess to them. In the end, just be confident! And if you aren't, then fake confidence. Good luck (:

^ youve said it already so preach

>>1 Depends if you want to make her interested in you first, or if you just want to let her know.
If it's the latter, it's easy, like >>2 said, be honest and tell her that you want to get to know her more. Also you might want to choose an appropriate occasion. If she's sitting in the bathroom, or eating or talking with someone, it isn't really nice to barge in and blurt out something like "I think I like you!", as well as waiting in front of the previously mentioned bathroom for her, or staring at her while she eats while you wait to get your turn, or standing silently in front of her conversing with someone while you 'wait'. It makes one uncomfortable. Choose an occasion when you are alone, or if you're sly, try to separate her, even if it's only for a bit. You want you guys to be in your own bubble, especially if the environment and their expectations can influence how she recieves what you say. BUT! Don't sweat too much over it. If you're trying too hard, it might still be better just to take your chances in the situation as it is. It's manlier than unnecessarily being a maximalist with it.
If it's the former, you might want to do some bantering. Be nice, be funny, it doesn't matter what you say as long as you make a good impression and get her attention, the goal is to make her associate her meeting with you as something positive, so when she thinks about you, it will make her happy, interested and open to further meeting you. Also, it's a good opportunity to find out if she's really what you expected her to be.
Whichever it may be, ganbatte.

You could always tell her. I mean just come out and say it. Dont be blunt saying things like you want to do her or anything, but you could always say things like "hey i really like you and we should get together sometime.

I think it depends. If you're trying to impress her or something then don't be stupid about. Having heard many a story from my father about trying to impress girls, they usually ended with him injured and not actually getting the girl. In fact, here's a hint, my dad didn't pull a stunt to impress my mother.

But if you're just trying to tell her then try to connect it with something she's into. For example, back during my freshmen year of high school, I had a guy confess to me by using Ouran High School Host Club references. He pretty much said he was Tamaki and I was Haruhi. Now the sad thing is, it took me all of fourth period to piece that one together but it was actually really clever of him because at the time I was pretty much "one of the guys" and our gang was pretty much a real life parallel of the OHSHC group. It never amounted to anything but it was still a really clever way of confessing and it was a subtle enough way that he could have played it off as something else in case I had been completely against it.

Blatantly saying you're interested works. I hate when people have to complicate things.

Thank you everyone! You advice has helped me greatly :)

For a good example of what NOT to do, watch pretty much any rom-com movie/tv show/anime.