O.K. you want something like a long line Bustier, they go down over tummy to keep it flat!
Hair I would say up doo with a few curls hanging down on sides and back.
Shoes I would go flats because you will be drinking.

I have very little help to offer but a formal that includes Margaritas in my opinion would require a little color.
That's all I can recommend though I may be wrong.

But giantesses are hot! :)

Suggestions:

As awful as they are, Spanx. Honestly, I'd go with a pooch over Spanx.

I'd just go boring and do strappy black sandals. Dress is long and you won't see much of them anyway.

Curly hair down, I'd say. Or maybe a sleek high ponytail, which I love.

I think your hair up would be pretty because of the neckline and detailing on the dress...maybe some curl strands hanging down...hopefully you could find a strappy kitten heel if you really dont wanna wear heels!...haha...have fun!

1. Maybe something like this...



2. A messy updo with a bit of volume would look nice.



3. As far as shaping items, Victoria's Secret has great shape wear...

http://www2.victoriassecret.com/collection/?cgname=OSBRPSHAZZZ&cgnbr=OSBRPSHAZZZ&rfnbr=5229


Also I think a pop of plum in your purse would be perfect for this outfit maybe something like this...

Since your dress is long, take advantage of it and wear some super comfy shoes. Black seems obvious, but if you want something that stands out, go with a colored shoe. Maybe a deep red?

As far as the hair goes, I say just do a simple knot in back and some nice face framing pieces?

I have a shaper-slip from victoria's secret that works pretty decent.

Cristina said Giantesses are hott. She is right. As a very fashionable guy, I can't stop thinking about the free margaritas.

I think that your outfit needs alot more color maybe like a green or a bright color that looks good on u and maybe like a dress that comes to your knees but in the end it is all up to u that is just my personal opinion................

well I have a list of shoes that you can check out in My "Shoes" list. I love the dress, definitely a steal, I think you should put your hair in a bun updo bbecause if your hair is down you'll cover up the lace detail on the dress, which is really pretty

Hair up somehow...show off the pretty lacey detailing of the dress. Shoes, you tall girls are killing me. Heels! Don't be bashful. Black or maybe silver? strappy sandals. You will look awesome. :)

What gabba_a said! I think the messy up-do would be oh so sexy. Shoe wise you could get away with so many different styles. Strappy sandals, peep toe sling backs, and satin are the first things that come to mind though. Zappos lets you narrow results by heel height if you don't want high high heels (which I wouldn't suggest anyway if you will be on your feet a lot anyway). That dress is so perfect for a formal event! What a great find.

Wow! Love your thrift find! I think all the do's posted by gabba_a would be appropriate, and as for shoes, maybe something like

http://www.kaboodle.com/reviews/report-signature-womens-corinne-pump-8

I agree with the long line bustier for both bust and waist control. Herroom.com also has some nice ones as well as suggestions. If you don't want to wear a high heel then go with something comfortable. I like glittery jeweled shoes but that may not be your taste. I think you should wear your hair up but not anything complicated. You should be having fun not worrying about the pins in your hair.

I think you'd look great with a messy bun. From the picture of you I don't think you need any support. I've used Spanx but I felt like a sausage all night, so you'll be happier without it. As for shoes, I agree about adding some colour.. maybe turquoise or even a metallic? Anyway, you look gorgeous in that dress :)

I agree about adding some color, but I wouldn't do anything too bright. Muted colors like the bag gabba_a posted will keep it formal. I'd love this dress with a messy bun with a long tendril coming down on one side of the dress (kinda like what we're seeing in your first picture).

i love the plum purse too! i think you should go with flats, forever21.com has really cheap ones! your hair would look pretty in a messy bun or even a low side ponytail, it looks very polished and is super easy to do!

i agree with a messy up-do those are sexy, formal and classy! shoes...hmm go for the ones with straps to keep the formal yet sexy look. awesome dress!!!

gabba_a has some terrific hairstyle recommendations! i love the low side pony tail like lisa_kate also recommended. messy is sexy and would be striking with your dress.

i also agree with the other suggestions of a punch of color. margaritas are fun and don't forget, mexican! so think color color color! think vibrant for a clutch. i would even spice it up with some bold colors shoes or at least sparkly shoes like your dress neckline. sure, not many people will see them, but you'll know you have them on!

i'm with nocreativity on this one. i think a loose bun would be perfect and very classic. you can accessorize with pearl hairpins, or something equally simple and delicate.
i'm with the whole "giantesses are hot" choir, but if you're going to feel uncomfortable, go with a kitten heel that will lift you off the ground an inch, and still have the dainty effect that heels give.
there are tons of great pre-code era heels that will greatly compliment the dress.
go for the full silverscreen glamour goddess effect and choose a pair of silver heels (peep toe, t-strap, you get the idea here...).
someone mentioned turquoise earlier, that's a great choice!
also, i am loving that dress. spot on for getting it at that price!

maybe silver for shoes and messy up-dos are in! Your long hair would look great that way!

I got married recently and I wore 'Flexees' undergarments - scary looking but worked miracles.

For shapewear, go with Spanx, or Sara Blakely also has a line at Target called assets that's very affordable.