A good base is
1 large carton of strawberries
1-2 carton of blueberries
1-2 ripe banana
other great things to add when in season are:
pineapple
peach
nectarine
raspberries
mango
figs
Cut everything up and mix it in a bowl. Try to mix enough sweet fruit such as figs and bananas so you don't need other sweetener.