Great suggestions here.
Just wanted to add: (from experience with my daughter as a toddler).... for some kids, restaurants can be very over-simulating... and noisy, and too much going on. For my daughter, she didn't like certain restaurants (even the kid friendly kind) because it was just TOO noisy for her... and she'd basically get fussy/screaming/uncooperative, and just not at her best.
Once she started to talk, she basically told us "It's TOO noisy... it's too much..." and we had to learn from HER... that some venues was just not the best for her. ESPECIALLY when she was tired as well. So, we learned what restaurants were conducive to her and which were not. THIS affects their behavior, too.
For young children, they don't have the best "coping skills" yet... and thus, they act out, and this is merely a way for them to "shut-out" what is discombobulating them. It's a "hint" to US... as to what is uncomfortable for them.
So, it was not a matter of her being "difficult" when we went out to eat... it was a matter of she not being able to handle certain places... the noisy, busy, bustling, over crowded restaurants. And her "having to" bear it, because at that age, it was all just too much for her.
So, there are these aspects as well, for some children. We have to observe what and where we take them. Some places just not being positive for them. For my son on the other hand... he's more noise tolerant and not as "sensitive" with these places. But he is just a typical busy active 2 year old who can't sit still... so, we adjust to that, and don't go to restaurants when he is tired (which is not a good time for him to be "patient" for US). Or if some restaurant is just too over-stimulating... he will basically tell us "not happy. Go home, now..."
So, see what makes your child tic. This can make all the difference sometimes. Sometimes, there is a reason for their behavior at certain places. And especially at this age... they just CANNOT sit still and be quiet and be "mild" at restaurants. It's just hard for them... they feel confined.
When/if you go to restaurants... ALWAYS ask for take out boxes right away... just in case you have to leave, due to an unhappy baby/toddler at the restaurant. This is what many parents do... plan ahead and be prepared to just leave. Many parents also simply do not go out dining at this age... because it is too hard, or just a hectic ordeal. When a child is able to, then it gets better. It's all about "ages and stages." Keeping in mind, that from t his age up through 3 years old... it's tricky going to restaurants.
All the best, just some ideas,
Susan