I have various sorting systems.... We have 4 of us, with a new tiny bubs who has limited clothes in the really small sizes (5 zeroes at the moment!)

I'll tend to wash colours every 2-3 days, probably 3 loads a week.
I'll do one white load a week (usually weekend so it has the weeks worth of DH's work shirts).
One each of sheets and towels on the weekend
Every 4-5 days I do a load of DD1's bibs/smocks and flannels she uses whilst eating. There's usually some food left on them still so I don't want to mix them with other clothes.
I usually also do another load of DD2's 'sick towels'
Another load of swimming stuff after swimming lessons....

So I guess I'm doing 9-10 loads a week! Wow, seems heaps when I write it like this. No wonder I feel like I'm always doing washing!

Tips wise:
I fold when getting them off the line.
I also try to get all of each persons washing off at the same time so I just go into a room at a time and leave the next 'section' of the washing basket there.