Pruss gave me some great pointers on practicing tasting. When the tobacco has a sweet flavor, try pinpointing what type of sweetness. Is it more of a deep molasses, or a caramel, or a brown sugar, or is it fruitier, like an apple or cherry?
If you get an earthy taste, is it deeper like the aroma of a swamp, or like a fresh plowed field, or is it brighter like freshly cut hay? He had a list of coffee tasting notes that I used to practice with. I tried using a list from a cigar tasting card, but I found the coffee one to have more of a range that translated better for pipe tobacco IMO.
It's just practice, and it helps you notice things in your tastes. And, it helps you understand when tasters say things like cherry or hay notes, when you might be thinking cherry as in an aromatic. Also, it will help you better notice that the tobacco is changing flavors as the bowl progresses. Sometimes a tobacco might start off all deep and chewy, like a wet baseball glove, and by mid bowl those flavors have transformed into nuttier flavors, like freshly roasted peanuts.
Then try using your notes from that blend to compare it to smoking it in a taller more narrow pipe, or a squattier wide chambered pipe. Make notes for yourself with several different pipes, and compare them. I think you'll start to notice more subtle changes in flavor.
As for perique... don't be afraid of it. I will occasionally smoke it straight, and it really is not big deal. I have no idea whatsoever why someone would be afraid of it. The worst I can say is that it gets very monochromatic in flavor. Same with smoking straight latakia. It's really nothing at all to be weary of. In fact, I enjoy doing this from time to time. Especially straight perique. It isn't a very strong tobacco by itself at all. But, mix the same stuff with a burley, then it gets strong.
