folding T-Shirts, Sweat shirts, Towels etc.

lay flat front down, fold tail over, fold sleeves in. Roll into a tube.
Store vertically in rucksack. Horizontally in draws & shelves. Removing from rucksack is easier. Ditto draws, shelves you may need to restrain the ones on top but because there is less surface area it is still easier than laying them flat one on top of each other.
Added bonus you can see more items in one vista - so choosing is easier, unless you are bad at choosing!

Hint it doesn't work so well on a draw full of red T-Shirts! (70 since you ask).

However I have a trick of: folding more than just the sleeve on one side and roll from the other. This puts any logo partially in view. Very useful because I like my logo to have some humour and some jokes are better than others in certain circumstances.