Here are a few tips on loading a moving truck, but here's the paramount concern: NO DEAD SPACE! Spaces will allow things to shift in transit, and that's the biggest source of damage for your items. 

Other tips:

* Make sure each box you load is packed full, otherwise, it might collapse under the weight of other objects you place on it.

* Have enough padding to protect your items on the truck.

* As far as packing the truck, try to use moving boxes that are industry sized: they'll fit together on the truck more efficiently, and the less 'dead space' between items, the less likelihood that loads will shift in transit (as mentioned before).

* You may put some items on their ends, like sofas, to get things to fit together more tightly (stretch-wrap these items to avoid getting them dirty).

* If you don't fill the entire truck, make sure you secure the load so it doesn't slide backwards during transit. 

For more information, see this article on loading a moving truck.