Add water and lemon (or lime) juice to a small bowl and sprinkle gelatin on top. Let the gelatin soak for 5-10 minutes.
In the meantime, blend the berries (or other fruit) until smooth. Add 1-2 tablespoons of water, if necessary.
Other flavor ideas:
For fall flavored gummies, try using pumpkin puree instead of fruit. Replace lemon juice with water and add seasonal spices like pumpkin pie spice mix.