what are the best ways to preserve.....?

Some things you simply can't freeze. For example; freezing a banana will just turn it into mush (though that's great if you're making banana bread!). While there's no way to stop it's aging process, there are ways you can help it age without so many bruises.

Buy a banana hanger (http://www.bananahanger.com/). This will help prevent bruises by eliminating surface pressure.

Don't pre-cut lettuce. Cutting lettuce destroys the cellular structure and assists in the rusting of the edges. Before service, bathe the lettuce in ice water, dry, then serve. The ice water will help perk up the lettuce.

Tomatoes can be refrigerated, but clearly they undergo a texture change in the fridge which most people don't even seem to care about. You can pop apples in the fridge as well as most other fruit and vegetable.

Also, don't be afraid to use fruits and veggies that're canned or frozen. Just because they aren't 'fresh' doesn't mean they're bad... in fact, they are sometimes better because they are flash frozen at peak of their freshness as soon as they're off the vine/ out of the ground, unlike the raw food which is off the vine and looses nutrition every single minute that it's sitting on the Wal-Mart shelf, waiting for you to buy it.

You can freeze your vegetables. Sometimes, my mom buys stuff in bulk and divides it in equal portions and just thaws it before. Actually, techniques like flash freezing is good because it keeps the nutrients intact longer. You can always pickle your vegetables as well. As for the fruits, I freeze fruits like grapes but it's all a personal preference. I doubt all fruits can be frozen.

I have same problem and it is to do with how they are stored BEFORE we get them.

When I was younger carrots/apples etc. would last thru the winter, now they barely last a week.

In storage they are prevented (somehow ) from ripening.( I guess gas)then when they are sold , the ripening accelerates faster than normal.