I just make a huge container of chopped melon, apple, pear, orange, tinned pineapple (cos I cant stand chopping that!) and leave it in the fridge covered up until I want it, normally lasts a couple of days cos my daughter eats it as well. If I want to add banana I wait to chop that in when I am about to have it otherwise it goes all icky!
IN fairness, I used to throw out piles of fruit and have only started doing this recently and I believe the water content is doing me good as well!