Flower4,
It's very common for kids this age to wanting to move around and not sit still.
We don't have a particular tactic. But most of the time, we only make them sit down when the food is served. When the food is here, they can sit down and enjoy their food. Before that, either me or my hub will bring them outside of the restaurant to walk around. If they fuss when we are having our food, either of us will have to pause to take care of them, the other parent quickly finish his/her meal, then take over. We have also tried to dine in children friendly restaurant that comes with play area, they play while we eat, win-win situation. iPhone is a hit too, but we avoid using it unless it's totally no other better way.