Well I am in the middle of planning a trip for 16 (we arrive in early November). I really didn't use much more than these boards and all the other info I could find as I stumbled around.
The first hurdle is to ensure that you book prior to 180 days out. We didn't do that since our trip was more spur of the moment. If you are trying to book meals with even larger segments of people, it's tough within the 180 day mark.
So this is what I would do now:
1. Of your group of 14, think about how you will divvy up the rooms. Will you all stay at the same resort? Do some of the smaller groups want suites or does everyone just want to deal with regular hotel rooms? Is anyone trying to save money and, if so, would offsite work better for you? Maybe somewhat offsite like Bonnet Creek where you can get 2-3 bedroom accommodations?
2. Once you've decided where you are going, make your call to Disney (if onsite) and have the "heads" of the room on the reservation call so you can all be ready with the names and credit cards to secure the rooms.
3. As you are waiting for your 180 day mark, try to look at where you want to eat and get that mapped out. You'll need to know what the various groups want to do. Need to book a meal for 14? Have that ready. Do they want to break up some of the meals and have 4 people going one place, 4 another, and so on. All that should be decided, annotated, and ready for your 180 day dining reservations.
4. Get your touring plan down and situated around your reservations (or vice versa if you can) and then start mapping out fastpasses. Same thing: will you all be touring together? Then one person should book the FPs. I just booked for my group of 16. It wasn't as hard as I thought. I new which rides we'd all want to do and which we didn't and it somehow worked out well (and was fast).
That's my starter tips!