I write the names of blends I haven't tried on sticky notes, stick them on the wall, place a monkey in front of the wall, give said monkey a couple of darts, and get the hell out of the way.
Just kidding, I look for blends similar to what I like (tobacco reviews makes this easy), and read the reviews while looking for key descriptors of my likes/dislikes. I'm more likely to take a chance on a blend that may not rate very highly or is described as not very complex but it has descriptors of what I like vs highly rated blends that are complex but contain lots of descriptors of what I don't like.
Like:
tangy, sweet, citrus, dark fruit (especially this one), honey, cool burning, not harsh, etc.
Dislike:
woody, smokey (a little is okay), burns hot, etc.
JimInks is very good a providing descriptors and sometimes what he doesn't say is just as important as what he does say.
Case in point: Sutliff Sweet Virginia #707. Even though it contains the word "woody", this is overridden by "citrus", "sweet", & "honey". Sipping or just smoking very slowly avoids any "harshness". "Uncomplicated" and "requires little though" are adequate descriptors here but, to me, that's part of its charm. A tasty blend that lets me just sit and relax and turn off my thinky melon for a short period. Perhaps "un-contemplative but entertaining" would be good a descriptor.