Things I've Learned From The PastStart actually making gifts a bit earlier, especially those things that kids wants to help with. I once forgot to plan around our business Christmas rush, and things got a bit hectic.
Pick a theme for the kids again. Last year was cooking for Hannah, building for Thomas, and photography for Allan and that worked so well! Extended family who wished to give gifts had a general theme to work around that was based on the kids' likes, and we were able to do some really fun stuff (actual functional cooking tools for Hannah, real working tools for Tom, just like Dad's and books, film, camera case etc for AJ).
Start working on things for the youngest family members. Our family only give Christmas gifts to the kids, as all the adults have their birthdays from late November through to January.
Simplify the meals even more. Too much time was spent cooking, and that takes a lot out of the day. Plan menus early, and make ahead as much as possible. If you have a freezer, you can make your puddings and cakes now and freeze them. They will still mature, and will be fresh and delicious for Christmas.
If you are planning on a party this year, start now to plan the menu, guest list, pick a date (if you do it now, you'll be sure to get your guests). If you want a particular theme, start to choose the decorations etc. Budget for the cost - save $2 a week towards the nibblys, drinks etc. Start to buy drinks that will keep until Christmas if you have the room to store them, but don't be tempted to dip into the store before Christmas.
I'm going to spend the next few months contemplating and jotting notes, but I won't start organizing and planning in earnest until October. By then, the shops will have their Christmas things in, and as I've already thought out what I'm doing, I'll be ready to tackle Christmas. Without the stress!