Here's a few tips:
If you have anything you don't use anymore or hasn't left a box since the last time you moved, get rid of it. There's no sense in moving stuff you haven't touched in ages.
Pack all the small stuff in boxes first & set it off in a corner. It'll make more space for you to move the bigger items when the time comes.
The day of the move, load the big stuff into the truck first, then pack the small stuff around it.