Before you pack, step one is to go through the dresses and take off the detachable bits. You can leave the waist ties, neck ties, ribbon stuff. Anything with a brooch backing (Meta's dresses tends to have a lot of detachable bows) runs the risk of making holes, or scratching up fabric, so remove that and pack it seperately. Anything delicate (like floral pins) should be packed seperately in a hard box to avoid being damaged by squishing. Label them all clearly.
Then, turn the dresses inside out. This way if some pressure causes the print to transfer, at least it's similar print to similar print (since they're all facing inwards).
Then pack them using whatever method you find the easiest. Honestly if you have the equipment and space I'd just go with vacuum bags, with the hangers packed with the dresses. When you get to the other side you can simply put them up straight away (you can flip them right sides out later on, but at least your closet will be unpacked and fully available).
If you can't or don't want to do vacuum packing, then I'd suggest this method (for dresses with skirts that don't have built-in petticoat): Lay the dress out. Fold the bodice down towards the skirt. Fold two sides of the skirt towards the middle. Starting from where the bodice is folded down, roll up the dress. If more skirt fabric starts coming out at the sides, just fold them towards the middle again and roll right over. It takes up the least space but they don't really like to stay rolled up, so you need to constrain them. Either tie a ribbon/slip a headband on them, or pack them into smaller laundry bags, then pack the laundry bags into your box.
(There's a vid of some chinese lolita packing her dresses like these for travelling btw)
For dresses that have a stiff petticoat, don't roll it. Do the same bodice fold, fold the skirt towards the middle, and do one more fold above where the petticoat starts. That's about the most you can do without damaging the petticoat.