To make a quality smoothie, start with a high quality blender. We prefer Vitamix blenders, but almost anything will work if you're careful.
Add liquid. This can be water, milk, yogurt, or fruit juice.
Add something frozen, whether ice, frozen juice, or frozen fruit.
Add fresh or canned fruit or vegetables to taste.
Add any extras, like spices, peanut butter, protein powder, powdered vitamins, or whatever your heart desires.