I feel this is important to anyone just joining, but share your biggest planning mistakes or regrets here!
My biggest mistake was ordering the vases before anything else; we got a massive amount of great quality, large and obnoxiously tall vases for an amazing price. We were so excited for them. I didn't even factor in the amount of flowers needed to fill those said vases, and our (real) flower quote skyrocketed due to the sheer size of our vases. We have to do faux to even attempt to stay in budget.