This step is really the most important. If you decided to hire professional movers to pack your belongings, then the hard part will be done for you. Many moving companies offer a professional packing service. These services are normally very good but also very expensive. Keep in mind though, movers use lots of wrapping and boxes. The average 2 bedroom apartment uses between $200 and $300 in just packing supplies so that is a large part of their costs.
If you are packing yourself here is an easy checklist
Packing may be the most daunting part of your move but with good preparation you will do a good job.