It depends o the person and their style, but my generally i'd say:
HAIR AND MAKEUP;
Find a foundation with as little SPF as possible, no more than 15 because it makes your face look paler pictures. Make sure you conceal and blend well. You'll probably get a bit sweaty if you're jumping and dancing around, so either use setting powder (any pressed or loose powder) or a setting spray (urban decay do a nice one, but its around 19 pounds so a bit pricey. Elf also do one, for about 3 pounds but it STINKS!)
Fake eyelashes can be a bit tricky, but they make SUCH a difference! Especially in photos! They just make your eyes look huge and gorgeous! I personally like the eylure ones in (i think!) 217? Really thick and really long anyway! If you dont want to spend the 7 poundsish on lashes, have a look in savers and homebargains ect for cheaper ones., but i recommend buying a seperate glue. Revlon does on for about 8 pounds which lasts AGES.
If you're wary of strip falsies, you could always try the individual lashes, which take a little longer to apply, but look really natural.
Always wait for the glue to go tacky before applying, and go over the lash line with a good liquid liner to blend the strip lashes to your own.
HIGHLIGHTER is your friend!! Apply a shimmery white to the inner corner of your eye and a teeeny bit on your brow bone, aswell as applying a highlighter to your cheek bones. I personally benefits high beam, but mememe do a cheaper version. If you don't want to spend money on a highlighter, you can use a little bit of a light shimmery eyeshadow to the top of your cheekbones. I like to apply it in a 'C' shape, from my browbone, down my cheek bone and stop just before where my eye starts. You can also apply highlighter to the top of your collar bones and down the center of your legs and on the top of your cupids bow.
I always use a MATTE bronzer just under my cheekbones to make them stand out more. Take the bronzer up onto your temples to blend. Use blush on the top, outside of your cheekbones rather then on the apples of your cheeks.
I personally won't go out without fake tan, but thats just me.
Take a hair bobble out with you .... even if your hair looks gorgeous and glamorous at the beginning of the night, chances are it'll be stuck to your head after a few hours. I like to throw mine in a side plait when it begins to annoy me, and a lot of my friends do messy buns. It might not look its best, but its better then looking like a sweaty frizzy mess.
WHAT TO WEAR:
Legs OR clevage, never both! It looks trampy to have it all on show, not sexy at all!
Make sure your dress covers your bum, and if it doesnt and you STILL want to wear it, put a pair of nice, and full knickers on! I saw a girl the other day in a stringy, greying thong ... ew.
Outfit and makeup always, in my opinion, looks better contrasting ... if you're wearing a slightly sluttier outfit, pair it with neutral makeup .. a soft eye and nude/pale pink lip ... but if you're wearing a more conservative or plain outfit, play it up with either a smokey eye or a stronger lip colour.
Always make sure you're comfortable - you won't enjoy yourself if you're in an itchy top, or don't like how something looks on you.
Take a good look in the mirror before you go out, and be totally honest with yourself - no breathing in or stretching your back ...after a few drink you wont be sucking in your tum, so why lie to yourself now? The camera won't be that forgiving. Ask yourself what you'd think if you were looking at another girl and not your reflection?
I would say make sure your shoes are comfortable and not too high ..but i won't because it would be hypocritical. ...when i choose heels...size matters! The bigger the better!
PICTURES:
Try and work out your best angles ... personally i look best from the left side with my head slightly tiled forward.
Turn your body so the camera will catch it on its side .. its much more slimming that a full frontal picture. Slightly bend one knee ... slimming! And put your hand on your hip to avoid bingo wings.
But at the end of the day, just enjoy yourself! You're only young once, and who cares if you don't look that great as long as your having fun?? When you're an old lady remembering all your wild times, you won't be thinking ''thats the night my hair looked amazing'', you'll be thinking ''this is the night that so-and-so pulled whoever and this person fell flat on their face!'' or whatever!