As you know from reading my posts, we made it a point to bring our son out to stores, restaurants, etc. when he was young so that we would get accustomed to it and would learn how to behave properly. And he has. So we continue to do it and recommend that everyone does it. (Note here: we work around his schedule for outings and meals, we do not drag him along to suit our needs). It has worked out very well for us because we do not have to go to kid-centric restaurants, but can go most anywhere and he is well mannered. So much so that many of the waiters and patrons actually comment to us about this.
Once it was time for the transition from bottles and ready to eat packet meals to real food, we had to find a way for our son to be able to sit in his highchair and be able to eat off a clean surface (we do not trust him with silverware or breakable plates). This is where @MightyCleanBaby Disposable Mats come into play. The first key is that they are disposable. Use them once and they are gone. And they have a sticky border that you can use to attach them to the table surface so it does not slide around while our son eats. And another nice feature is that they have designs, shapes, colors, etc. that can help keep our son entertained while we wait for the food to arrive at the table.
These mats have been extremely helpful for us and we cannot imagine having a meal out without them.