How to get a girl's attention?

Make her laugh.

Well first of all, you don't need to take anyone's attention, you need to be yourself & if you meant to be with someone, you'll take their attention without doing anything.

Second of all, make sure to be yourself (important) never try to copy others, never try to fake your behavior, never try to be someone that you're not. Or you'll be screwed literally.

Third of all, learn the level that called "appropriate" . Right now some dear people suggested *making smile,giving flower ect .. Also i'm about to give my own suggestions) but you need to know when to do something,when to say something, where to do it & how to do it. Not cross lines, not to cross her personal space ect . . .

Now, "If you wanna take a girl's attention, you need to show  your "Attention" first.  But that entirely depends how much you guys could be close from the first place.

-Listen to her words,listen carefully when she has something to say,agree with her, support her, defend her statements in front of others, back her up,let her know if she needed any help, she can counts on you, never disappoint her when it comes to it, try to find out her favorite categories, then do different creative stuff around those faves, (for instance, she loves a band, find a rare thing about that band like a published book & give it to her, or find out her favorite color & choose your clothing by that color, or get her favorite perfume & use it ect . .stuff like that) open up discussions about her favorites, try to make her smile, try to make her happy,  confident her, makes her to believe in herself, makes her to believe in her abilities to move forward & reach her dreams, be there in important events, if she felt sad, try to built her up, if she felt happy try to take a share & makes her more happy, when she get something that she wanted, be the first person that congrates her, be one of the first people that wish her birthday, flowers are good too,attention of every detail of her appearance, see the hairstyle, the way she done make up, dressed, be polite, make polite compliments, admire her, try to pick up the right words, words are magical,  make sure you learn how to express them & yourself.

ect . . .!

Be yourself, give her some flowers.

Yeah, just be yourself. Sometimes we can tell when a guy's being obvious in trying so hard to get attention and we don't like that. If you like her then tell her directly. Or you can start by asking her out.

Be yourself.

Give her some flowers and some of my shine