Start with a model with great skin, use a great makeup artist, and you’ll cut down your retouching tremendously while getting better results.

Once that's done...

Many retouching novices blur skin to achieve “clean” results. Unfortunately, to an educated eye, this is extremely obvious and unrealistic; blurring skin is virtually never a good idea for commercial or high-level work where realistic results are required.

In some portrait or glamour situations where the clients are less demanding and the time/cost tradeoffs are different, however, judicious blurring may be acceptable. In those cases use of the healing brush, clone tool, followed by a light application of a blur (Gaussian/median/anisotropic/etc) to the skin may be acceptable. Tools like the Skin Smoothing Plug-ins listed in lll’s lll's Photo Software List may save a little time over doing the blurring manually.

Angelo Lorenzo Photo’s thread Basic Pore Smoothing Technique gives a step-by-step description of an effective blur-based approach.

A more time-consuming approach, but one which gives far more realistic looking results is described in Ronald Tan's Basic Pixel Level Dodging and Burning Tutorial MM thread. Another thread describing this technique is Christos’ Understanding Skin Retouching Regarding LIGHT thread.

An offsite) guide from Glitterguru (Suzette Troche-Stapp) goes through this and more.

Also check out older threads on this topic. (Most of those discuss the less desirable blur-based techniques, however.)

Kevin_Connery wrote:
My list of recommended Photoshop books for photographers is here. It's very different than the ones I'd recommend to a graphic artist, but make a much better foundation for photo-imaging than most general photoshop books.

The linked page has reviews. Here are just the titles and authors for the retouching ones.

Retouching
Photoshop Restoration and Retouching by Katrin Eismann & Wayne Palmer
Glitterguru on Photoshop: From Concept to Cool by Suzette Troche-Stapp
Commercial Photoshop Retouching: In the Studio by Glenn Honiball
Digital Retouching for Fashion, Beauty, and Portrait Photography in Photoshop CS3 by Gry Garness

Gry Garness' might be the best for you, based on your stated experience. But see the comments on the linked page as well.

Also...

From the Photography Forum FAQ

How do I get great-looking skin on a model?

Wow thanks a lot!!!! I will go and look for them right away

Thanks a lot!
Maria