i always wear a semi-formal dress to a wedding, shoes always wedges because my parents insists for me to wear high-heeled shoes and i can't wear 'normal' high heel shoes. i don't wear other accessories, a necklace at most. make up is always natural for me, damn i can't even put on eye shadows lol, since you don't wear make-ups probably a base like bb creams and concealer, natural eye shadows if you can put or have someone to put it on for you, i usually only wear eyeliners, and sometimes mascara too, just mix and match lip color with your dress, and don't forget eyebrows!

Either a simple dress or a formal blouse and skirt (I would go with pencil skirt). Don't wear white. Rule of thumb is to never dress more extravagantly than the bride. I'd recommend flats for comfort and formality. Light makeup should be fine.

The basic rules of going to a wedding are, don't wear white, don't upstage the bride in your wardrobe, and don't upstage the mother of the bride in your wardrobe.

It depends very much on the kind of wedding, but if it's anything vaguely formal or if there's a formal ceremony of some kind, go for something smart and pretty. A dress would be best, but you can get away with a nice skirt and blouse. If you're still in high school, avoid suits. Prettily dressed = formal while you're still in school :)

As for shoes, either go with a nice black pair or just anything that goes with what you're wearing. Don't overdo it on jewellery or makeup or you'll look like you're trying to upstage the bride. Can't give any extra advice on that since I don't know what you look like and makeup advice isn't my strong suit anyway.

Accessories - you'll probably want a clutch of some kind big enough to put a phone/camera in. If it's a formal ceremony, then sometimes a little fascinator is nice as well.

i think a simple and elegant dress would be more than enough , its doesn't have to be extravagant , and if you're not used to heels you can always wear flats but its totally up to you and your style

as for the makeup i always do this look for the eyes ( brown shadow all over the eyelids and use slightly darker shade over the crease of your eyes and just simple liner ) its simple and easy and hard to mess up with

I try not to wear anything too outstanding, personally, but anything that looks more formal than your regular clothes will do! Even just a smart shirt and maybe a skirt or something would looks pretty classy. You don't always have to limit yourself to dresses, haha. And because it's a wedding, I say go crazy with the makeup because you can.