As a newbie myself, I've had good luck finding what I love (and don't like) by starting broad and narrowing it down.
1) Get 5 or more different cobs. Even if you have briars, hold off on using them at the very beginning till you have a better idea of what you DON'T like so you don't flavor what could be a your favorite pipe with something you never want to taste again.
2) Check here
http://agingfaq.nocturne.org/touchstones.php to get a sense of some of the choice examples of the different major categories. Try tobaccoreviews.com to hone in on the blend that seems the most appealing, and be sure to ask on this forum!
3) Go to your brick & mortar tobacconist, or barring that, try online stores, and try to get 1oz quantities of each of your choices, 1 or 2 from each category. I know pipesandtobaccos.com has a very wide selection of premium tobaccos available in this size. At $3 - $4 a pop, its a great way to try blends without breaking the bank and being stuck with a bunch of something you don't like.
4) Pick up some small bail-top, or mason jars at the hardware store. Anything that seals properly is essential. Most likely your 1 oz tobaccos will come in baggies, which aren't suitable for locking in flavor for very long.
5) Try them at your leisure. Be aware some tobaccos may be moist, and may need to dry out a bit. Take out a bowlful and put it on a paper towel and let it sit for as long as is necessary. A rule of thumb is, if it feels wet, of if squeezing a bit between your fingers causes it to clump like clay, it should dry a bit. Read up about packing and smoking techniques online, and then get ready to smoke. Find a comfy place, relax, take your time, close your eyes, and focus on what you're experiencing, as if you were trying a fine wine. Really set your mind into exploring the tobacco's nuances, how it changes over the course of the bowl, etc. Try both inhaling from mouth to your nose, and just exhaling from your mouth through your nostrils, to experience the flavor. Some taste better one way, some the other, some both. I try to limit myself to 2 bowls a day, one in the morning and one at night. Keep in mind that some tobaccos, especially the strong latakia blends (and for me, virginias) may taste great, but nuke your olfactory system temporarily, so the next tobacco you smoke may taste different than it would if you gave your mouth, nose and throat some time to recover. I take a non-toxic, odorless colored marker and mark each cob on the bottom with a different color for each different category, so I don't get them mixed up. I keep a little chart of when I smoked each pipe last, so that I can give them some time to rest a bit and absorb the juices from the last smoke.
6) Keep a log, describing taste, aroma, and anything else you notice. You will probably find some have just what you want, some are boring, some are plain torture. Try to give each one a fair chance (ie. don't just smoke one bowl and make up your mind), sometimes what you ate that day can effect the flavor.
If there's anything you have that your really can't stand, DONT junk it -- put it back in its mason jar, seal it tightly and put it away. It may just need to sit for a bit, or maybe your palate needs to evolve on its own volition. You may find its the perfect taste sometime in the future, and be wondering why you didn't realize it at first!
After that, its time to find the category of tobacco (or two) that you liked most and delve in. Choose a briar or several to dedicate to that category. Explore it by trying different types, by different makers. Move up to 2oz tins if you can't find 1 oz bulks of a particular blend. Some of the best tobaccos you can smoke, such as GL Pease's blends, were hard to find n 1oz quantites, but they're so good its worth the risk once you have an idea of what type of blend you enjoy. With any tobacco, as long as its in a category you like, there's a good chance you will like it and not be throwing your money away on something you can't bring yourself to smoke.
And if you've found something you absolutely love, get more, in honest-to-goodness manufacturer sealed tins. - I prefer several small portions versus one big one, so I can cellar the other ones in their vacuum sealed state.
And be wary of aromatics. Not only do they seldom taste as good as they smell, and when smoked don't often taste or smell
anything like they do out of the tin, they change the taste of a briar (and it can be a real pain to get that taste out), and they have to be smoked very carefully or they taste awful and burn your mouth. Additionally, as it's cheaper to smother bad tobacco in a flavor, than it is to have pure tobacco taste good on its own, there's alot more low grade, trashy aromatics than there are natural blends. If you want to explore them, do your homework first. They do have their moments, but finding something that lives up to what its title and packaging promises is a hobby in and of itself (for me, I've only found one, Dan Tobacco's Sweet Vanilla Honeydew Melon, that is truly delicious)
Above all things, take your time, savor it, and remember it's about relaxation and
enjoying yourself.