Terre d'Hermes can be pretty tough for even experienced noses to precisely pin down. You may be trying to smell immediately after spraying, in which case, yes, all you're going to smell is the alcohol used as a fixative.
If you're just looking to be able to discriminate a bit better about what's in colognes you're shopping for, start simple. Is it sweet? Spicy? Does it remind you of anything you encounter in your daily life? Does it conjure up any visual images or trigger memories?
I will tell you basically how I started was I made extensive use of the Basenotes Directory, and made a spreadsheet in Excel. I wrote down the "notes" of the fragrances and when I saw the same note across two or more fragrances I noted it. Pretty soon I had a neat little web of not only what made scents similar, but more importantly what makes them different. Take, for an example, Diesel Fuel For Life. When I'd started this hobby if someone told me to identify one note in the composition I probably wouldn't have been able to, but when I look at my reference and notice it's the only thing I've tried that lists raspberry as a note, I find it much easier to pick up on. Kouros, for example, has a very nice Jasmine note. Baldessarini by Hugo Boss has a fir note (like the tree), and if I hadn't first read it I probably wouldn't have been able to pick up on what exactly I was smelling. It's at the point now where I can smell a fragrance and tell what is different about it compared to other fragrances; a lot of them are going to have repetitive elements, such as bergamot (a citrus fruit used in 1/3 of all mens frags and about 1/2 of womens) in the top notes, patchouli, vetiver (a type of grass), amber (resin/sap from trees), and musk in the base of the fragrance.
If you're slightly more serious about trying to peg individual notes there are several "perfumer's toolboxes" that have essential oils of commonly used ingredients.