1. If you had a lot of advance notice that you are moving, make a list of every company that you receive mail from over the course of a year. Then, armed with that list, change your address with each of these companies.
2. Make and distribute address cards to all your friends and loved ones.
3. Separate your belongings into three categories - stuff you want to keep (no matter what), stuff you could do with or without, and stuff you want to get rid of.
4. Start spring cleaning. No matter what season it is. Whether you are giving up tenancy or selling your home, you will need to scrub it clean.
5. Pack up anything that you can do without for 2 weeks or more. Better to get more done earlier than less done never.
6. Enlist help. If you don't have enough volunteers ready to help, hire someone. Seriously. It's not worth doing it yourself.
7. Rent a moving van. Seriously. It's worth the money.
8. Contact the person you are getting keys from, and who you are giving them to. The more overlap the better. If you give and get possession the same day, try to get possession as early as possible and give up possession as late as possible. Then at the very least you can make two trips if you need to.
9. Have your mail forwarded. There will always be something missed.
10. Last and most important: Make lists! No matter what your packing style or time-frame, lists make everything easier. This covers everything from what you're keeping and what you're getting rid of, to what goes in each box, to what you need to remember before the big move.