Whatever you do, don't let them overbalance to either side, the worst that can happen is for you to twist your ankle, and I would know.
It's like, you step, and somehow your foot twists and you are like walking on the side of your ankles. Bloody painful.
Yea, anyways, I'll shut up now.
I have so many blisters from wearing heels, yeah they cane but I love wearing them. I dont really have to becuase im tall, but I love them. I can walk around in them all day. I do however, love my ballet pumps, I can seriously wear them anywhere!
Ok back to the question. The best advice I can give you is wear them all day today so you can break them in and reduce the risk of blisters (usually you should do this one-two weeks before event, but we havent got that much time!). Use small slow steps to start off with as others have said. And when you are confident try walking a little faster. In your bag, be sure to put some elastoplast in, could save your life! Have fun!
I'm a regular wearer of high heels, I too struggle to walk in them, indeed, it is difficult to find pretty shoes that fit my feet.