Sort whites from colours and fluffy items from dark to avoid needing to do extra treatments; sort drying into piles of similar fabrics so that if you must use the dryer it’s on for as short a time as possible.
Sort heavy garments from lighter garments, washing them first to give them more drying time.
Sort washing into easy to manage groups to make hanging and folding easier. I always hang in "people" i.e. I hang all my things together, then everyone's clothes in turn.
This means that as I take things off the line and fold them they are already sorted, ready to be put straight away. Putting the washing away is a breeze because it is already sorted.