Yes believe it or not there is a right way and a wrong way of how to pack a backpack. Get it wrong and you will find that your backpack will soon get very very uncomfortable. This will then affect your whole trip, making it a miserable experience rather than one of enjoyment and pleasure.
There are slightly different ways on how to pack a backpack depending on the kind of backpacking or hiking you intend to do. For instance if you are hill walking or hiking on steep rough ground most of the time where balance is the most important aspect, then the heavy non-bulky items should be packed lower for better stability.
For more normal day to day backpacking such as trail walking where you are more likely to be hiking on mostly level ground, the heavy non-bulky things should be packed higher and near to your back. This keeps the load close to your centre of gravity, and helps you keep an upright posture.
I’m not a great fan of having lots of things strapped to the outside of my pack. To me this not only looks untidy but these things are likely to get lost or damaged. The only exceptions I would make would be my waterproof jacket and trousers, so that they are easily accessible in the event of rain or showers during the day. I also used to strap my kip-mat to the top of my pack, but as I now use a ¾ length inflatable mat this goes inside.
My backpack has a separate lower compartment and in this I put my sleeping bag, I don’t use a compression stuff-sac as this tends to make the whole thing into a solid lump.It`s much better to use the rucksack compartment as the stuff-sac itself, then it will not leave empty corners, and when the pack is put on, the waist-belt will help the whole thing to contour to your body, making it much more comfortable. My inflatable kip-mat goes in after my sleeping bag helping to push everything into a nice fit.
At the bottom of the main compartment I put my spare clothes; the ones that I will not need during the day, such as spare socks, underwear, tee-shirts etc. on top of them go the smaller heavier things such as wash kit, repair kits, personal items and anything fragile. Then on top of that goes a jumper or fleece so that everything is cushioned between two soft layers.
The tent goes in next; the poles are carefully slid down into the pack so that they are at a corner near my back. The actual tent I like to have packed in such a way that it can be flat in the pack and not rolled up into a cylinder, this takes up less space and can be packed down tighter. On top of this I put any food and water that I will not require during the day and also a warm jacket.
Into the lid and side pockets go my first-aid kit and the food and water I will need for the day and anything else that I will need to use often. This way whenever I stop for lunch or just a quick brew up every thing is easily at hand and I don’t need to go searching through the main pack just to find one thing.
All that you need to do now is make sure that the whole backpack feels comfortable and well balanced, this is best done by putting it on and walking around with it for 15 or 20 minutes. This should let you know if anything needs to be adjusted or moved. This is obviously just a rough guide and will depend on your personal preferences and the type of gear that you decide to take. But the most important thing is that it feels comfortable as its you who will be carrying it.