If you want to be a true vegan or vegetarian you need to educate yourself on both. First ppl will tell you you can't get enough protein as a vegan. It is untrue a complete myth. Ppl on plant based diets are the healthiest ppl on the planet. You will run into crazy ppl on both sides of the issue. My wife has been a true vegan and gluten free and is running a half marathon. She doesn't do it for crazy reasons she's not an animal rights nut she just believes its the best thing for her. There is a place in NYC called blossom it is vegan and I have gone with her a few times. I enjoy it and I'm not a vegan. Most important whatever your reason for wanting to do it educate yourself. Good luck
Just a few tips from a Pescetarian;
1. There are so many vegan/veggie recipes packed with protein, I suggest getting a used cook book online. I usually try something at a restaurant and then look it up to get some ideas. I recently discovered tofu "eggs." Simple and delicious
2. My other half does the food shopping and it seems Trader Joe's / Vita Cost have the best prices on groceries.
3. As far as restaurants if your ever on Brooklyn, Park Slope to be exact, there's V Spot and 'Snice. Candle Cafe on UES or UWS, is expensive but worth the trip.