Have a lot of packing tape. You can never have enough.
Mark on all sides of box what room it goes into. This way the movers do most of the shuffling around. You can use numbers instead of words and tape the numbers on doors and walls so the movers know where to put the boxes.
Probably half the stuff you are packing you do not need. I mean it throw some stuff away. You will wish you had when you are unpacking.
Separate the items that are sentimental or valuable and move those yourself. For example my gaming computer was in the car not the truck.
If you are using any type of pods make sure where you are going they can fit etc. I have read horror stories that certain pods could not always fit due to size or local government regulations etc.
We always try to feed the movers on top of a tip.It is a nice gesture and the movers always were grateful.
Measure the doorways to make certain you can get things through it. It helps you to prepare. For example do we need to take the legs off the desk to get it through the door? This can save a lot of time on moving day.
Some things will break it is going to happen. Some things will get lost, it is going to happen.
It can help to put the things you will need right away specially marked. Like a pot to cook in so you do not have to try to figure out where oh where is a pot on you first couple days. Kind of like first day boxes so we have our essentials out whatever it might be.