i need advice.

i don't really know but i think আপনি should just be yourself he should like আপনি for আপনি

There was a movie on this, I don't remember the name... But just be yourself, that's what he likes about you! What আপনি wear depends on where you're going. আপনি don't need to wear a prom dress to a movie theater, but আপনি don't want to wear a t-shirt to a $100 restaurant.

Well, be yourself is the best উপদেশ I can give আপনি on how to act.
Don't act clingy অথবা anything like that.

What to wear: Wear what you're comfortable in. Don't try to look older and don't try to look younger, look your age but smart and independant, meaning don't wear anything sluty.

What to say: That is really just be yourself again. আপনি have talked all বছর right? It should be as easy as that. Talk about anything and everything, interests, films আপনি do and do not like- stay away from depressing subjects and things like your family because normally people complain and it's a major turn off. So, don't complain unless it's in a jokey way, like wow look at the dinosaur, is it supposed to be real? It looks like a hand puppet!
Sorry, that was lame but it's all I can think of right now.
Good luck!!! if আপনি need anymore adivce, just ask!

Well... Since you're 14, I guess he's 14 too? So I don't know his personality অথবা anything, but based on his age, I would say that আপনি need to take advantage of your own body. Use what আপনি have. High heels may also be something to consider. আপনি have to decide what color you're gonna wear, I don't know if you're spring, winter etc, অথবা anything about him, so I can't say much about that...

But the most important things, are:

1. Touch him a lot
2. Always laugh of what he says
3. Give him compliments
4. If he doesn't pay for the dinner, then throw your soda/water অথবা whatever at him and walk away.
5. If he paid for the dinner, then give him a চুম্বন after the date. If আপনি forget it... Poor guy...