The quality of wine can never exceed the quality of the fruit/grapes used to produce it. In other words, don't use distressed fruit, use the good stuff. Following a few simple guidelines will promote sound wine production.
If corks are brittle from an opened bag, low humidity or just from being very old, it is difficult to know how long to soak the corks before they become mushy. A technique you can take advantage of to make the corks pliable enough to insert is to construct a cork humidor.