Throw away anything from your last move that you never unpacked. I'm pretty sure I have boxes from end of year college move outs that are still in my parents' basement. I graduated in 2003. That stuff should be thrown away...
Be ruthless about getting rid of stuff- if you haven't used it in the last 6-12 months, it goes bye-bye. If you have a hard time parting with stuff, try to find a friend that can use it. It was way easy to give a friend the ice cream maker my MIL gave to me for Christmas a couple years ago than to hand it over to goodwill or ebay it.
Play the minimalist game - get rid of 7 things today, 8 tomorrow, 9 the next day, etc.
Label your boxes very specifically - not just the room, but what is in them. If you can handle the extra record keeping, list contents and record in excel for easy searching. I used to live in a very tiny apartment, and we had to use offsite (landlord provided) storage for some of our stuff. I would open up my excel file and search "camping equipment" and know that I was looking for the Blue Tote #2 for my stuff or Brown Tote #3 for DH's stuff. So much better than guessing!!! Suggested columns are container, location, item, owner. Maybe this isn't as helpful for a move where you are quickly unpacking it, but if you might take a while to unload everything, it is a nice resource. Also, I'm a big excel nerd and this is my kinda thing.