As another old lag who's been flying PA28s for far too long, I can see the point behind most of the posts above.
I was taught that for soft field, don't stop and rev against the brakes. Set two stages of flap (ie not the third, drag flap). Keep moving, feed in the power smoothly as you line up, keep the weight off the nosewheel but not with full up elevator, and accelerate in ground effect. That will work for any pilot, and there are graphs that tell you how much take off run and distance over a 50 foot wall you need. They seem to work, with the standard adjustments for wet grass, tailwind, etc.
HOWEVER ... I fly an Arrow (taper wing), and that has a CAA note in the POH recommending that flaps are not to be used for takeoff. I'm glad it's only a recommendation (not a mandatory instruction) because getting out of grass strips would be extremely difficult without flaps. Two stages, set before the takeoff run starts for me - I'm not good enough to cope with pulling flap while accelerating.