These are some things I have come across over the years that can help you on your wedding day.
Choosing your Date - If there is a vendor that you HAVE to have, keep in contact while choosing a date to make sure they are available.
Emergency Kit - Sewing kit, meds, safety pins, bobby pins, stain stick, deodorant, floss, Band-Aids, feminine products, a snack.
Get matching hangers for your dress and your bridal party. They don't need to be anything fancy, they could be all black velvet hangers. But you don't want a bunch of mismatching hangers in your photos.
Hang your dresses up, out if their bags prior to your photographer showing up.
Have your flowers, jewelry, shoes, invitations etc all in one place for detail shots.
Try to keep getting ready clutter (bags, purses, clothing, etc) in 1 area so its not all over the place in your getting ready photos
If your dress has Button that have the elastic loops to pull over them, CROCHET HOOK!!! It will save your fingers and time. A bobby pin works in a pinch.
Your Dress. Make sure there are multiple people that know how to bustle your wedding dress. Practice it. No one knowing how to bustle you can cause delays.
Make sure you eat something for breakfast, the day goes by fast, you don't want to make it to dinner and realize you haven't eaten all day.
If you have littles that will require more attention and naps, think of hiring a baby sitter so all adults can be present in wedding activities. You also don't have to worry about who has your little one.
Don't panic, the ceremony cant start without you.
If you plan to wear heels in the grass, get heel savers so you don't sink and destroy your heels.