Lots of ways to go about this: one way is just to keep reading here, with particular attention to review topics, like the OTTIs. These have included lots of green teas, some puerh, a little oolong, but it should help fix some of the usual terms in your mind. A good book can also help--I learned a lot about how to taste teas from the Harney & Sons guide to tea, which features a bunch of comparative tastings. Even though it's not possible to recreate the tastings entirely, it's helpful to taste similar teas as you read along iwth the text.
And then, any term you can come up with that is sufficiently descriptive to make your meaning clear to most of us is fine. There really isn't a standardized vocabulary out there: some things are easy, like nutty, but there is a quality out there that I've had a heck of time trying to describe, associated mostly with greener oolongs, that reminds me of late summer pasture, grass turning golden, warm, sunny, and with a rich, sweet smell, and I'm still trying to find a way to describe it in fewer words than that.