First divide your white wash, one of pure white and one of baby stuff with colours on it. Wash the stuff with colours on a seperate wash with a colour catcher sheet.
Wash everything on a 60 intensive wash, no pressing the quick button. Greyness lies that way.
Wash using twice the usual amount of detergant, and 6 dessertspoons of washing soda.
Dolly balls can be bought from lakeland and sometimes aldi, they pound against the wash and get more dirt.
Use a dylon or dr beckman whitening product (homebargain do dylon 4 for a £1.
Do not put anything in that isnt white, none of this "oh I've had it years and its cream so it wont run" it will.
I only use sains basics bio powder and soda crystals with a dylon sachet every few washes and my whites are very white, I have white bed sheets, towels, tea towels, napkins (you get the idea, I like white).
If you get any stains put basic cheap bleach into a spray bottle and spray it on, cheapest quickest way to get red wine, tea, curry stains out.