Shep's book is timeless. His tips are just as valid today, as they were back in the day, when we read them in the "Tips on Building Diorama" brochures in our Monogram kits. I recommend it for your library.
I second Al on visiting Alan and Marion Ball's site, they are Grand Masters in the figure hobby (MFCA and other awards). The URL is www.mb-miniatures.com/.../home.php
Also, I recommend visiting the sites Timelines/Historica, www.timelinesforum.com, and PlanetFigure, www.planetfigure.com. Those are the two main websites, in English, for figure painters and sculptors. you will find a lot of useful info, including ongoing SBS's by people sculpting and painting figures, as well as lots of images of finished pieces, and lots of additional info.
I also recommend the German forum HZ-Forum. It's in German, but a lot of the members speak English, too. It's run by Conrad "Conny" Schulte, who also runs the online figure and supply shop Fredericus Rex. I recommend it for the same reasons I recommend Timelines and PlanetFigure.
The Clubhouse (http://theclubhouse1.net/) is another very good site to visit. I just joined it recently, on the recommendation of a friend who was already there. Lots of content on sculpting, across a variety of subjects, though you might have to join to see some of the content.
You can also find tips on sites that aren't painters/sculptors forums per se. The Maschinen Krieger forum, maschinenkrueger.com/forum, dedicated to models based on illustrations by Japanese graphic artist Kow Yokoyama, also has a lot of content that is instructive for someone looking to learn to sculpt.
I'm teaching myself to sculpt, too, so, that's how I came up with this list ;)
Hope that all helps, and let's see your work!
Brad