I don't mean to give you yet another tip you probably already knew, but I've only recently realized this, and it's sort of changed my life.
I buy a lot of fruit. Sometimes Sam goes on a fruit-eating binge, and sometimes she eats nothing but crackers and air (that's where we are right now). While I love fruit, there's only so much I can eat before I find myself with an epic tummy ache, yet throwing out overripe or rotting fruit makes me even sicker. I find this is a particular problem with berries -- strawberries, raspberries and blueberries are among our favorites, but geez, you have to eat them in, like, a day.
So what I do now, when I start seeing my fruit get that ganky bruised look is this, and forgive me the obvious simplicity: I cut it up, mix it in a bowl with two teaspoons of sugar and VOILA! Your fruit is preserved. For like, DAYS. A *week*, even. An extra week! Of slightly bruised berries!
They, ah, taste better, too. And two teaspoons of sugar per pound of fruit is pretty negligable, calorie-wise. Worth it. Worth it!