Plan Ahead - You already know from planning Christmas with your entire family how hard picking one day can be, so imagine the time it takes to work out an entire week. In a study done by CheapAir.com they found that the best time to book a flight is 54 days in advance . So be sure to get your dates and destination set early!
Involve Everyone - You'll want to be in agreeance with everyone on where and when you are going. If you have young kids you'll also want to make sure it is kid-friendly, but also still have things the adults and grandparents can enjoy too.
Be Aware of Everyone's Finances - When planning a large group trip make sure to keep in mind every family's budget. Sometimes these trips are paid for as a gift from grandparents or another family member, but there are always unexpected expenses to consider as well . No one wants to go on a vacation where they can only do the minimum because of their budget, and watch other members of the party taking every excursion possible.
Communicate Packing - Since everyone will be traveling to the same place, not everyone needs to bring their own hairdryer. Talk to your other family members to see who wants to bring what for everyone to share.
Look into Alternative Housing - Hotels are great for small family trips, but when you are traveling with 10 plus people renting a house or condo may be the better option. Some great website to search for rentals include Airbnb, VRBO, and HomeAway.
Consider a Travel Agent - Planning a large trip can be very stressful and hard to find all the best travel and lodging deals. Travel agents can take a lot of stress off of you, and they are educated and experienced on how to provide you with the best possible vacation for your family and your family's investment into it . If you decide that you would like to consider using a travel agent, Central Travel offers many amenities and experienced agents who can find the best vacation to suit your family's needs.
 The Best time to Buy a Flight is 54 Days Out… Or Is It?, CheapAir.com
 10 Tips for Multigenerational Travel, Family Vacation Critic
 10 Reasons Why you Still Need a Travel Agent, Fox News