Depends on what kind of party is that. Simply I can say wear those clothes in which you would feel comfortable and stylish.
If you want casual jeans and a tank\ or a dress and heels
What you should wear will depend upon the type of party. If the party is more casual, you can just wear pants and a top. If it is more formal, you should wear your best, such as a dress or tuxedo.
Yes, Any one should wear blazer with jeans to a party. But, That should be perfect match and attract others.
I think you should come to FashionTIY. There are lots of clothes for the party.
Well, you can dress as anything you want to be, because you have a right to dress as anything you want to be. If your friends disaprove of your costume, then they were never really your friends.
Men should wear a coat and tie and for the ladies a cocktail dress (no gowns, no pantsuits, no blue jeans or formal wear for either sex.) A guy casual pants nice sweater if your a girl almost anything but aviod jeans and to formal of dresses.
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a dress
Go out in what you came in wearing...nothing!
You should wear a black jeans with white frock, it is very dashing dress and best for all types of children parities. You should organize some tableau or something new to increase fun in your party. If you want to get more entertainment, then you should arrange this huge event at any play center, play lands and other funny out siding places.
Semiformal means a suit and tie for men and a cocktail dress for ladies.
if it is a girl it should be a aqua dress and if it is a boy it should be a tux.