If you're thinking about going vegan, you're gonna have to change a few things in your normal routine. I found it easier to eat and cook vegan, after I gave my fridge and cupboard a small make-over. When your kitchen is "vegan", it'll make things a lot more convenient when cooking. Who doesn't want cooking to be easy peasy?
Of course, your grocery list and kitchen-staples are gonna depend on your taste, location and which type of diet you prefer. But I found that most vegans have some foods in common, that they just cannot live without
Here's a list of the staple things, I always keep in my kitchen:
Veggies and legumes
Plant-based milk (my favorite is rice milk)
So these things are just my basic foods - I eat them every single day and they fuel my body all week. Of course, I use so many other foods and spices for recipes and special occasions.
I would also recommend you to get a blender and a foodprocessor (a lot of vegans recipes requires these)