How to cut your hiking supplies' weight in half?

My aunt and I are going on a two week long hiking trip in a couple of days. We will be hiking along the coast of Southwest England, through the wilderness. And we will be carrying everything with us (except for a tent and a sleeping bag).

Since I am not a good hiker at all, I am concerned about the weight on my back quite a lot. Before I would put anything on my packing list, I always weighted several items on my kitchen scale and decided to take only the lightest of things. To my surprise, the weight was still ending up at 12 kg (more then 20 lbs) and that was quite scary. For two months I was thinking of the tiresome travel with these 12 kilograms of 'stuff'.

Tonight, I made a great discovery! I realized that in the 'Grand total' weight, I also included the subtotals... Yes! I am that bad! I don't care though because this has just cut my hiking weight to only little over 6 kilograms. And that is much better than 12 :)