I usually do DD1s white school shirts, white towels, white socks, my white undies and bras, DS white PE top together on a white wash, sometimes il chuck DD1s white knickers with pink bows on or DD2s white vests with yellow trim on in too cos im a rebel ;)
Then i do a dark wash, Black jeans, underwear, DSs navy school jumpers, DPs black socks, my jeans, leggings, DSs school trousers, DD1s school skirts etc etc
I also do a 'red' wash which is DD1s school cardigans, red tights, DD2s red dress, DD2s leggings, DSs red rugby shirt, DPs jack and jones hoody etc etc
I do a colour wash which is most of the two girls stuff as its all pink lol, my coloured tops and skirts, any coloured underwear, DSs tshirts
I also do a lights wash that are not white but still light, so like pastle colours mainly my pjs and the girls clothes. Some of DPs tshirts.
Never put anything dark in with whites and never put colours in with lights and ive been ok so far. Only time it went wrong was when i was in hospital and DP put his red hoody in with DD2s light blue top and it turned purple, which he got really told off for lol