I was vegan (I’m now omni b/c I’m preggers and my resident seems to have a thing for surf ‘n turf. And ice-cream).
My best advice is to first think of vegetarianism (or veganism, even) as a means of EXPANDING your existing diet, not restricting it. Some people can just go cold turkey (ha!) and that’s great, but I think that it’s an easier transition and more fun to start off with a commitment to be vegetarian 3 days a week or every dinner or something like that. That’ll help make you excited to explore all the different kinds of foods and dishes that are vegetarian in a healthy way–a lot of people who DO go “cold turkey” tend to rely at first on a lot of processed food (veggie burgers, soy hot dogs, etc. etc.) and a lot of pasta. This is not only not that great for you, but it gets old fast. This is a way of expanding your reperatoire and learning about cooking new foods (some vegetables you may have never tried before) so that you build up a familiarity of what you like and what makes you feel good.
Here are a few great cookbooks I love:
“Plenty” (I forget the author–very sexy and popular, though!)
“Moosewood Cookbook” (series, Mollie Katzen)
“How to Cook Everything Vegetarian” (Bittman)
“The Tassajara Cookbook” (Brown)
“The Vegan Mediterranean Cookbook” (Klein)–her lemon oregano potatoes and no-cheese pesto are ama-zing!
Also, although dairy is considered vegetarian (not vegan, though), you can still drink milk and call yourself a vegetarian. But there’s plenty of milk alternatives (rice milk, hemp milk) for you to try. I like vanilla almond milk (i like Trader Joe’s brand unsweetened) if you can’t do soy milk.
And finally (I swear, this is my last point!), don’t sweat small things. Sometimes new vegetarians and vegans think that it’s a “lapse” or they’ve “cheated” if they have a burger. It’s YOUR diet, your body, and your choice. So if you find you can’t live without a little bacon now and then, it’s okay. A few strips of bacon on Sunday, consciously purchased and eaten, is surely better–for you and the planet–than bacon all the time.