Determine who's paying for what, right up front. Her parents, his parents, bride & groom, lay all the cards on the table so that there are no surprises. Remember to communicate with all involved, even though it's your wedding.
Use your imagination, cut where you need to. Start by paring the guest list and send announcements to those you couldn't invite ~ they'll still love you and be so excited that you found that special someone, and you'll save a lot of money!
Happy planning ~