To increase yield, put dark plastic cylinders around the young rhubarb, like you would asparagus... makes the leaves grow taller trying to reach the light, so the stalks are longer and slimmer, thus making sure they are not thick and tough. They will be paler, white and red, rather than pink and green, and you should indeed pull rhubarb, taking the outer leaves first as the older and more likely to be ripe.

That's what my dad always did anyway, don't know if it worked, I hate rhubarb.

LTS