For a healthy smoothie, too much fruits is not so healthy as it has loads of sugar. I choose one fruit I like (berries, strawberries, pineapple), I add a healthy fat (avocado, raw nuts, nuts butter), greens (handful of mixed greens like kale, watercressm spinach, chard, etc whatever I have in the fridge), liquid (filtered waterm coconut milk, almond milk, etc I dont drink dairy milk), 1tsp of healthy sweetener (raw honey, dates molasses, etc), seeds (chia, flaxseeds, hemp), & ice cubes. I also add supergreens powder but it's optional.
I make a similar smoothie for DS almost every day. I also make green juices but they dont always taste yummy loool.