Not all wrinkles are created equal and some are actually good. They make you look human. No sand blasting, remember? So forehead lines, laugh lines, and other significant wrinkles should remain. You may want to reduce them somewhat (remember it's just a darker shade next to a lighter shade), but you want to keep them.
Good retouching is about taking a few years off of someone, not genetically re-engineering them. People are not pefect and attempting to make them so usually doesn't work out well.
Thinner, smaller wrinkles are usually fine to get rid of, especially the ones underneath the eye. Although again you want to be careful about making it look natural. More significant wrinkles can be made shorter and less 'deep' by dodging and burning. Both Jane Conner-ziser's DVD and Katrin Eismann's book have detailed techniques for doing this in Photoshop.