Moving preparations take time so you should start doing it as soon as the move is decided. Before packing though, make a checklist of the tasks you need to do so you will not forget anything.
You should go over your things so you can pick out the things you will need and use in your new home and separate them from those you need to discard. After doing so, you need to estimate and get sufficient packing supplies. Remember that if you want the packing process to go faster and smoothly you should not run out of packing materials. 
You also have to take care of the school records of your children and make sure that they are sent to their new school. Of course, you need to find good schools for the children early on so their   academics will not be disrupted so much.
You should not buy so much frozen food especially as the move draws near. Instead, you should start consuming them because it would only inconvenient to bring them to your new home. It may even get spoiled if you are traveling long distance.
Make sure to notify banks and subscriptions about the change of address so bills will get to the right address. Subscriptions would also be delivered to you. Utilities need to be transferred as well so your home would be complete with working utilities. You will not have to pay two bills as well.