Make sure your house is organized. If there is stuff you want going with you, not them. Be sure to separate it accordingly. Pick a closet or a room, whatever it fits in, and tell them they are not to take the items in that area. I had the movers pack my purse once... I had to unpack, which is not allowed but I had no choice. It took about 6 boxes and I found it. Whew! You don't have to disassemble anything... but dusted is nice, organized is nice. Like your Tupperware cabinet, we all have one that gets a little carried away when we aren't paying attention. Get your bowls all in order and stacked nicely. Easier for them to pack and unpack. Dust off the back of the entertainment center that you never really get to... it's nice that they can't leave you a love note in the dust. (Again, I'm speaking from experience here. LOL) But truly, you don't have to do anything... I've seen garbage cans with garbage still in them packed and shipped. That was just witnessing, not personal knowledge. You can do a lot of things to get ready for them but you don't have to do their work. It is just nice when it is a little more organized, goes a little quicker.
Personal knowledge on this one too... We had just bought a new VCR (it was 1992, they were still all the rage). I brought out the box, the Styrofoam, all that to package up the VCR and stereo equipment. The VCR isn't where it should be and it isn't in the box. I ask where is it? They say on the truck... nope, I want it in this box. But it's on the truck. Get it off the truck. I didn't follow the guy outside, my mistake. It came back in the house. A box far too large, no padding/wrapping, remote, wires, everything all in this box and no number tag. Yeah, that was in the cab of the truck going home with one of them... Most movers are honest, work hard, try their best to care for your belongings but there is also a bad apple in every bunch. So just keep an eye on what's happening. If you need someone to come over and watch with you, have a friend or a relative come over. It should go smoothly and I doubt you'll have anyone with sticky fingers... but just keep an eye on things. Also, any jewelry, take it with you, put it somewhere that it does not get packed, keep it with your person.