The way you pack a rucksack is extremely important. All of your kit must go in the rucksack so that the items that weigh the most are close to your back in the upper part. This is achieved by putting the sleeping bag in first, across the bottom where it will fill the base of the sack, and then work your way up from the least heavy to the heaviest items, putting them on top of each other and keeping them in place up the back by stuffing light items such as clothing down the front of the sack. The same applies to side pockets if your sack has them; put the heaviest things nearest your back and light things away from you. I am also careful to balance weights between sides to prevent more strain on one shoulder than the other.
So the next item on top of my sleeping bag is my rolled and flattened deflated ground mat, and then my Zephyros tent, with its little end poles removed so that I can fold the tent to fit the width of my rucksack. When the tent is wet or damp, which it is most of the time from rain, dew or condensation, it is rolled in a black bin bag to stop anything esle getting wet. The tent pole bag is slender enough to poke down one side of the rucksack and the peg bag goes down the other side (the idea being to balance the weight).
The sleeping bag and tent are logically out of the way at the bottom of the sack, as they will not be needed until the end of the day, while warmwear and anything to do with food is within easy reach at the top.
My plastic bags of powdered energy drink, powdered milk and muesli fit nicely into my plastic microwave bowl which keeps them together and protects them, while little items such as disposable lighter, knife, pillbox of sweeteners, and more, are kept safely in my titanium pot and wedged with a folded j-cloth on top of them; a thick rubber band keeps the lid in place.
By contrast with the least needed items, I put my waterproofs where I can get at them quickly and easily. The jacket is folded loosely in half and placed under the top flap, while the overtrousers are rolled up and held by webbing straps on the top.
Save the heaviest things for last, which in my case are always my food items, and keep them close to your upper spine, not away from it and not to either side of it. They are also near the top of the pack when you stop for a break. Hold them in place as described in the first paragraph above. I know from experience that this really helps to improve load carrying, stability and comfort. Pack your things any old way and you will constantly be aware of your pack pulling away from you while you are walking; the same goes for walking with a foam mat roll or jacket hanging from the rucksack.
Strangely, as I use my food up during my trip, my rucksack never gets to feel lighter, which it should do.
Finally, don’t let anything rattle or clunk in rhythm with your stride, because it becomes very irritating.