There is no exact science to smoothies, you kind of just have to play around with them and figure out how you like them. I prefer mine to be more on the frozen side so I regularly use fruit that I have frozen instead of ice because all the blenders I've had have never done well with ice. You really can put almost any fruit or vegetable that is easily blended into a smoothie, you just have to figure out the best combination. This recipe is based on one that I have been making a lot lately. I've never actually measured the ingredients before so these are just my best guess.
Tip for using vegetables: Always blend the vegetables first with your liquid so that they are sure to get really smooth. I'm ok with getting a chunky bit of fruit in my mouth but chunky veggies in my smoothie skeeve me out.
1/2 cup fresh spinach or more - I usually just fill up my magic bullet. Remember if you are using frozen spinach that it has been cooked down so it really is a lot more spinach than when it is fresh so I would half the amount of it you use compared to fresh spinach.
1 carrot - I found the blender handles this best if it has been peeled and then shredded
1/4 cup to 1/2 cup of a liquid (juice, milk, V8 fusion, etc...) - I use orange juice because it masks any bitterness that could potentially be there from the spinach
2 - 4 TBS of yogurt - you can use a yogurt cup or I find it more cost effective to just buy a big guy of plain yogurt.
1/2 cup fresh or frozen fruit - As I mentioned above I prefer to use frozen fruit, just make sure you cut it into smaller pieces so it is easier for the blender to handle. You can use any combination of fruit you want. I usually use strawberries and something else. I like to add peaches, cherries, grapefruit, blueberries, etc... Blueberries help to take away the green color by the spinach. Depending on what fruit you use this smoothie can be interesting colors
1. Blend spinach and liquid until smooth.
2. Add carrot, blend until smooth
3. Add yogurt and fruit and blend until smooth. Add more liquid if it is too thick
4. Enjoy getting 1 1/2 servings of veggies and 1 serving a fruit or more depending on what you add!