moving

I'm great at packing things into various spaces, a trait I get from my mom's entire side of the family (which my sister definitively did NOT inherit). unfortunately, I have a hard time deciding what should go into those spaces. it's a challenge to not make boxes too heavy, or waste too much space or put breakable things in a spot where something heavy might shift onto them.
I know everyone hates moving, but I tend to find myself sitting in the midst of all of my belongings not knowing exactly where to start because I never know what I won't need before I unpack, and then I start thinking about the unpacking process, and I just get completely overwhelmed.