OK, I thought about making a "something new" post, but I feel as though I don't need to insult your intelligence, dear readers. Ideally, the "something borrowed" should come from a happily married woman, so as to borrow not only her belonging, but her good fortune. I think so long as you are borrowing from someone you are close to, you'll be in good shape.
Veils are one of the easiest things to borrow. Ask around and see if any friends or family memebers have something that would work with your dress. If your gown is simple, an antique veil would be gorgeous, so ask your mother, mother-in-law, or grandmother if theirs can be used. You would be surprised what a talented seamstress can restore.
Can't afford a diamond pendant or diamond chandelier earrings, but you'd love to be wearing some the day of? Borrow from a relative or good friend. I don't think they would feel taken advantage of, and would surely be flattered you thought of them. I'm even working with a bride who has a great relationship with a local jeweler and he is letting her borrow anything in the store. I need to know how to find a friend like that!
Carrying a bible down the aisle is a tradition that dates back several centuries. Have a close relative loan you a family bible, or even borrow one from the church you grew up in. Your florist can create a romantic spray of flowers to rest atop the bible, so you will still have a bouquet. If your are Catholic, borrow a rosary from someone and have your florist incorporate it into your bouquet.