Load the heavy items that need to be moved first. This will place the majority of the weight closer to the center of the entire moving truck and near main axles. As a result, the truck will be more stable. Additionally, the items will not be under as much force from the inertia caused by turning. Usually, the heavier items that should be loaded first include items such as couches, pianos, dressers and cabinets, and other large furniture such as bed frames and headboards. These items typically are not needed immediately after the moving truck arrives, so they can be left in the truck if need be until the essentials (e.g., shower items) are taken from the truck and into the new home.
Try placing larger items on end. Some items that usually sit horizontally in the home can be placed vertically so that not as much space is taken up on the moving truck floor. These items include couches and desks, as well as other furniture. To do this, all that is needed is bungee cords that have adequate hooks on each end, or moving belts. Most moving trucks have anchor points for securing the cords or belts once they are wrapped around the item that needs to be secured, so it's easy to lock the vertically-positioned items into place. When this is done, make sure that the size of the bungee cord or belt is not too large---the cord or belt should be tight around the item with little leeway so that items do not tip and shift during the trip.
Pack the truck according to room as much as possible. For instance, place all the boxes with living room items in one area of the truck and all the boxes with bedroom items and clothes in another. This way, when the truck is unpacked, it is very easy to keep track of where items need to go as they are unloaded. This avoids the hassle of having to search all through the home for the box that has that one item that's needed later on. If the boxes are clearly labeled and movers know which room is which, it may not even be necessary to direct the unloading process, which leaves the person who is moving more time to start unpacking or take care of other details associated with the move.