What is a Vegetarian?

Let's start with the basics. A vegetarian is a person who abstains from eating meat, in lieu of a plant-based diet.
Whether your motivation is inspired by health, religion, ethics, or the environment, these are some ways to adopt a vegetarian lifestyle:

Eggs Over Easy: Lacto-Ovo Vegetarians

Lacto-Ovo vegetarians are the most common type in the Western world.
These are vegetarians who stick to a plant-based diet free of meat but allow themselves to eat animal by-products such as milk, eggs, butter, yogurt, and honey.

A Fish Out Of Water: Pescetarians

Pescetarians allow themselves to eat fish and shellfish in addition to their plant-based diet. Many use this stage as a transition period before becoming a full vegetarian or vegan. The mindset behind this form of vegetarianism is that the most harmful meats to eat are red meats. Also, fish contain omega-3 fatty acids, which are vital to metabolism.

Vegetable Heaven: Vegans

Vegans don't eat any animal products whatsoever. They abstain from eating meat, as well as by-products.
This is considered the strictest form of vegetarianism, and many substitutes must be used instead of animal byproducts such as soymilk and tofu.

Juicy Fruit

If you'd prefer to drink your veggies instead, juicing might be for you.
Juicing is entirely vegan, though this form is mostly used as a fasting or weight loss method.

Over the summer, I was inspired to go on a juicing fast after watching the documentary: Fat, Sick, and Nearly Dead.
The concoction consisted of kale, lemon, celery, cucumber, ginger, and granny smith apples.