Here's my two cents (or, things I learned from my wedding):

Fake flowers very rarely look any good.
Mirrors and candles can be found fairly cheaply and they're a quick, cheap way to make things look elegant. (Though places may have regulations on whether you can have "open" flames and such, so be sure to find that out)
If you go the "real-flowers" centerpiece route, you know real traditional-like, those suckers will eat up $60 a piece (at least) in a hurry.
Attach the word "wedding" to anything and the price doubles. Rice? 50 cents. Wedding rice? 5.00 a teaspoon.
Look up different types of flowers, find out what's in season. Things in season will cost less, and you can find cheap flowers. (like daisies)
The more you can do up front, the less hassle you'll have later.
It may sound like a good idea now, but hand-made, hand-tied tiny little gizmos will drive you nuts when you're trying to do 200 of them the day or two before. :)
You really don't eat THAT much of your wedding cake, so that's not something I'd sink your budget with. (A lot of couples have a 'fake' cake and then have sheet cakes from grocery stores in the back for the guests)
If you have an idea, ask around. There are cheap ways to get around expensive stuff.
You are inevitably going to offend someone, possibly multiple people, so just get used to that idea now.
Don't go with David's Bridal unless you must...and stay away from their "matching goodies" like guestbooks, pens, etc. They're SO a moneywaster.
Rick Delorme is a tool. :) (Sorry, had to say it)

Let me know if there's anything tangable I can do for you, A. I'll be looking for ideas to pop on here, but if there's something specific, I can be directed.