Make a list
Write everything down ! You'll thank yourself for it later. Create a simple computer printed list of numbers with a space to write contents. Place a number on each box and list the contents on the list. Such a simple idea that'll save you time and energy in the long run.
Have plenty of supplies
You'll need lots of boxes, probably more than you'll realise these can be collected from you're local super market for free, purchased on line or from your local hardware store. Wrapping materials are a must to keep your valuables save and sound also strong box tape to seal your boxes.
Keep things together
There's nothing worse than losing the television remote so pack it with the television, book ends with books and extension leads with the appliance, it'll make your life so much easier when it comes to the unpacking and setting up.
Designate a colour for each room in your new home such as yellow for your kitchen, orange for your dining room etc, apply coloured stickers on the boxes near the number that you've already put on it to mark what's in it. In your new home put a matching sticker on the door of each room.