I do most of our washing and hang our washing as follows:
Shirts; polo-shirts etc are hung from the waist but only one edge so they billow out in the wind. I hang them like this because collars take the longest to dry and dry better flapping in the wind.
Trousers, skirts and jeans I hang from the legs or hem. The reason being the waistbands take longer to dry and therefore benefit from flapping in the wind just as collars do on shirts etc.
Socks, I hang in pairs from the tops. I found that hanging them from the toes wear them out quicker.
Underwear? Well, we have no inhibitions with regard hanging them out. I'd never considered that anyone would take such an interest in their neighbours' undergarments.
I do, however, hang them by the waistband with two pegs so that the gussets flap in the wind and dry quicker. My wife hangs them with one peg. I must admit that, having read comments on here, all her underwear is sheer or lacy and that is very obvious the way I hang them. Two pegs are still best and she's never asked me to change how I hang them.
The only thing my wife insists on is re-washing after rain soaking.
My only consideration with regard to colour is; I don't hang whites next to each other just in case it makes some look grey or ivory garments look like dirty whites.
All our pegs are blue and don't have springs (which always broke quickly). They just push on and pull off and even hold well in gale force winds. A lot more expensive than spring pegs but last a lot longer and better in very windy conditions. Best weather being warm and windy.
We don't leave washing out overnight. Not because it might be common but for commonsense. They get damp from dew and the early morning birds mess have caused re-washing.
We dry towels in the tumble dryer because line drying makes them really rough.
I was impressed with reading about hanging sheets from the two ends instead of folded over the line. They do billow out and dry better that way, so, thank you for the idea.
I always use a prop to raise the washing as high as possible and never leave the pegs out as the sun harms them.