Hi Jatzntan, it takes time to develop your palate, I started attending cupping sessions run by one of the specialty roasters in my area and learnt a lot from those sessions. Also roasting my own beans has helped me in distinguishing the different characteristics.
I can now distinguish acidity, body, fruit, citrus, chocolate/cocoa, caramel, nut, earthyness, wood etc, Ive just scratched the surface and have a long way to go but thats all part of the joy of being a coffeesnob.
I usually do a long black and taste it as it cools, or a plunger as a means of testing and appraising my roasts.
If you want to taste berries/fruit roast some Harar to just on second crack.
I just roasted some Indian and it smells like nuts when I ran it through the grinder.