Read this tip to make your life smarter, better, faster and wiser. LifeTips is the place to go when you need to know about Dining Out Vegetarian and other Vegetarian topics.
As a consumer you have a right to know what you're eating and buying, so don't feel bad about asking. Restaurants are there to serve you. Always be kind in the way you ask, but you should have no problem at most restaurants getting served a meal consistent with your particular tastes or values. It might help to inquire about the ingredients as some foods have "hidden" animal ingredients that you might want to avoid.
I wanted to mention that you have to be very careful even when asking. I have a blog that has been looking into restaurant ingredients for vegetarians and vegans at http://www.goeggless.com. I normally rely on corporate offices, owners, and executive chefs. Last week I made an exception and went with a local manager as my source, only to discover later that he had given me incorrect information. So now I am only going to rely on the aforementioned positions for my blog.
some things to watch out for: lard in refried beans, anchovies in salad dressing (ceaser is a no-go in most restaurants!, fish sauce in thai food, things fried in animal fats, etc.