Homecoming dress to formal prom dress.

Well, I guess that depends how much time you've got and what kind of stuff you've got at your disposal.

Are you confident with a sewing machine? You could try taking the bodice off your dress and making a new one, so that you end up with something that's more of a typical 'prom dress' shape (i.e. the skirt sits on your natural waist). There's a tutorial with a pattern generator that might be useful, although I haven't tried it out: http://www.cutoutandkeep.net/projects/princess-seamed-bodice-pattern-generator

If you don't have a lot of time and/or you don't want to slash your dress to bits in case something goes wrong, you could try just adding some embellishments to it. See the band under the bodice? You could sew a new one over the top of it in an accent colour, or you could stick/sew on some sequins or other shiny stuff. You could try that on the actual bodice itself, although the pleats might make it a bit trickier.

Also, I've noticed that you've got some projects on your page using yo-yos and bows - why not make a bunch of them and sew them onto your dress? The picture in this tutorial is kind of what I mean: http://www.cutoutandkeep.net/projects/embellishing_a_dress
There are loads of tutorials on this site for making chiffon flowers and stuff if you'd rather do that. You could also make some for a hairband/some clips and coordinate your hair with your dress!

Another really easy (and cheap!) thing to do would be to whack some coloured tights on with it as well - worked for my prom dress :3

And one final, final thing - have you thought about making a dress from scratch? If your parents don't want to buy you a new dress because it's expensive then making one might work out cheaper. Make sure you leave enough time though (speaking from experience...)

Sorry it's such a long reply, I hope at least some of that is useful. You should totally post pictures after you're done as well

Is the skirt a circle skirt? I would say if it is, maybe add a long tulle tutu underneath it to give it some oomph. If not, maybe add a collar that's connected to the straps by lace that matches what's in the skirt.

Maybe all your dress needs is a pair of ankle boots and opera-length satin gloves.

I was going to suggest(if you are good at sewing) making a longer skirt, circle style

brain wave, what about making it into a halter.

or like I saw on my fave trashion blog, taking a lace shirt and layering it under the bodice to create a new look?

You can make it sleeveless or change the color of the sash on your waist. Maybe add something under the skirt to make it fuller.
Or don't do anything to the dress and just pair it with new and interesting accessories. Wear a colored shrug or bright heels.

YARITZA! <3 Are you going to prom?
The problem with simply just accessorizing differently is that I went with Tyler to Homecoming in it and if he's at Prom, I don't want him to see his ex in the same dress he danced with me in, you know? Especially if he acts like how he did at Homecoming at Prom. If he's going to look at me/try to make me jealous (like he tried to do to Bri at Homecoming) then I want to be looking amazing and totally different.

Anyway, my best friend decided she'd buy me a prom dress online and send it to me. :]

Yes, yes I am

Hmm, yeah I understand that.
But no matter what, you will look amazing. You can wear a potato sack and your inner and outer beauty will shine through.
<3

Thats great!
I hope I see you at prom

You should never worry about what some jerk guy would think about you. A-holes just aren't worth worrying about.

I always recycle clothes I'm bored with into something new that's still noticeably the same garment and guys and girls alike always think it's awesome.

Anyway, good luck with the new dress. Do you have a picture of the dress you'll be getting?

I do, it looks like so:

And, that's me

I do, it looks like so:

And, that's me

That's a really cute dress Are you going to wear a shrug or bolero with it?

No, I just wore it like that.