I also think that you need to keep a list of what is really important, fragile and also those things that are vital and will be needed within a very short time of arriving at your new place.
If you keep your lists separate you can also add them to your box when you label it so you know, from your list, what is in the box. When you first pack, it seems like you will remember where everything is, but after the move and feeling tired, plus all the boxes are now in a different spot and a totally different room, it's easy to mix things up. This can waste time and effort going through all the boxes just to find something that you really need.
Try to list things carefully and pack items from the same room or that are the same/similar types of things (like bathroom things from the cabinet) or kitchen things but separate foods from crockery, pans and other items.
Try to just keep your clothes all together, keep them in drawers and on hangers to make it faster and easier to unpack at the other end.
Lists and a bit of thought and preparation can really help when you arrive at the other end. Plus, you will know if you have lost anything. You can photocopy your lists on your home printer so that you can stick one to the box and keep the other one with you. Label the list according to the box number or name. This will also help you to know if you are missing any boxes or items at the other end.
@sebhancy's idea of listing the things you might not want to take or want to sell is also a great tip. If you start your list early enough it will really help you in the long run. Plus, with this tip, you can get rid of some extra clutter and make a few bucks to help with the moving expenses!