Like Wheatfield says...
Hard light yields hard images
Direct fill flash can make things even worse. Wrinkles are canyons in the skin and the flash just introduces a second set of hard shadows to the various cliffs and ledges.
A softening filter can help as can appropriate cosmetics and a shallow DOF. You can also decrease contrast and apply softening in PP. But even with these tools, the best approach is to avoid hard light. Shade, north-facing windows, cloudy days...all of these are your friends.
Steve
(Assuming you want a natural affect. If not, you can always go the "glamour shot" route...pancake makeup and high-key technique makes all the wrinkles, blemishes, noses, etc. simply disappear!)
Last edited by stevebrot; 06-21-2009 at 10:13 PM.