If a mainstream restaurant does offer a vegetarian menu, the menu will more than likely be vegetarian and not vegan focused. Do not let this hinder you. Some of the vegetarian options may be vegan, or can easily be made vegan.
First, if possible, call the restaurant ahead of time to see if they offer a vegetarian menu. Some restaurants offer a vegetarian menu that may not be handed out upon being seated at the table, but they do offer a vegetarian menu if asked. Many of these restaurants will also have the vegetarian menu as a downloadable menu on their website apart from the regular menu, so you can prepare yourself ahead of time in this manner. If a downloadable vegetarian menu is available apart from the regular menu, this may require for you to do a Google search or a search within their website.
Secondly, if a vegetarian menu is not offered, I do not settle for a salad. Everyone insists that salads are all what vegetarians or vegans eat. As we know, this is a myth that we plan to dispel when we order at restaurants with friends, co-workers, and family (smile). At the restaurant or before by checking out their mainstream menu online, I see what type of meal can easily have the meat-poultry-fish-dairy taken away to make it vegan (or, vegetarian if you are a vegetarian). Many options on the menu can easily have the non-vegetarian/non-vegan ingredients taken away that will not cause the chef too much of a headache (smile). Sometimes, only one ingredient may need to be taken away such as in a pasta dish with chicken and marinated vegetables in olive oil/garlic. You take out the chicken and the chef prepares the dish as pasta and marinated vegetables in olive oil and garlic. Another example is that I ordered a hot panini Mozzarella and tomato/roasted peppers sandwich from a cafe for a work lunch meeting, and asked the cafe to take out the mozzarella for a hot tomato and roasted red peppers panini sandwich. It was delicious as a tomato and roasted pepper grilled sandwich! I called the cafe ahead of time to make sure that this substitution could be done before the entire office ordering process, and the employee was delighted to fulfill my request.
I hope these tidbits help get the drama out of eating out at non-vegetarian /non-vegan restaurants. Relax. Smile. Take a deep breath and enjoy the holidays at restaurants!
~ Sister Vegetarian