Here is a green smoothie recipe that uses easy-to-find ingredients. Feel free to add any other ingredients to your liking.
Other Vegetable Ideas: Whenever I buy vegetables from the farmers market, they often come with the greens intact. Those greens, such as carrot tops, beet greens, or radish greens, are great for adding to smoothies. You can add a small handful of those greens in addition to the salad greens. I also like adding celery, cucumber, or zucchini to my smoothies.