Ok, a couple questions and suggestions:
1. How did you end up with a pressurized PF on a Gaggia Classic? I wasn't even aware they made them (one of the benefits of the Gaggias is that you get a "real" 58mm PF).
2. The number one tool you need to learn how to make good espresso is some good beans that everyone knows. Fresh roasted beans are ok (I've tried plenty of terrible fresh roasted beans though), but a blend that everyone on here has tried before is much better, that way you can describe what's happening with your shots, how they taste and most likely someone will have run in to the same problems before and can help. When I was first learning on my Gaggia I liked Counter Culture's Toscano and Caffe Fresco's Ambrosia, but anything from
Favorite Espresso Blends 2010 is probably good, just look for something that isn't too temp sensitive.
3. The number two tool you need is a good digital scale (which can also be a cheap digital scale). A difference of 1g can make a big difference in how a shot turns out, and consistency is key.
4. I think the Virtuoso is a decent grinder (I don't have any experience with it, and don't remember any reviews, but it looks like it has a real set of burrs as opposed to some "bean crushers"), but if it's not the Preciso you might run in to some problems getting the grind just right, but you can probably work around that.
5. If the grinds look all clumpy or aren't distributed pretty evenly after you dose them out then try out some simple ways to break up the clumps and spread out the grinds, but keep it simple and repeatable, it should be short and easy.
6. Don't worry about how hard you're tamping or any spinning or tapping or anything. As long as it's flat and level you're good.
6. Seriously, go look at #1 again, using beans that everyone knows and recommends is key, it takes the biggest variable out of learning the whole process. Once I found some beans that worked for me I just ordered the same thing over and over again until I had all the other steps down, there's enough to figure out without worrying if the beans are just too tricky or gone bad or something.