Well I'm usually avoiding being leg grabbed by not kicking, maintaining my body away from my opponent's and always keeping at least one leg on the ground, what guarantees me easy mobility. Leg grabbing is a really good counter to lift kicks or snapkick, but in case I'm leg grabbed I usually try to use my grabbed leg with another hand to control my opponent and let my other arm and leg on the ground and try lifting him, or I try dming/frac'ing him since he's with no guard. I'm not a pro but sometimes this works.