I was just thinking of posting this topic the other day! Guess you beat me to it!
I remember asking this question to one of the roasters in Melbourne, during a public cupping session they held.
One of the ways they told me to improve your palate was to just grab some fruits or any other food and to taste them.
So for fruits; grab some oranges, limes, lemons, grapefruits, mangoes, peaches, apples etc and just taste them and write own your thoughts.
For other types of food; chocolates (the various degrees of dark and milk), caramels, sugar (white vs brown), honey, steak 
and again just noting down how you taste them? That was the advice given to me.
I suppose it’s really just taking your time to analyse how the tastes are, training your palate and then writing it down in your own words which, will then help you to communicate the flavours you are tasting in your coffee.
Since then I’ve found a few other resources on ‘Training your palate for coffee’ on the internet.
http://www.jimseven.com/2009/10/16/8-steps-to-develop-your-coffee-palate/
James Hoffman’s guide, which dates back to 2009, is still a good guide in my opinion. Essentially buying two different types of coffee (or more if you would like 
) and brewing them side by side. Important thing to note is perhaps the practice of having a Point of Reference’, whereby you take one specific coffee and compare it to another different coffee. Blindly tasting without a point of reference makes it hard to hone in on a specific taste profile to compare others with.
Another guide which I like is that from Mistobox. Again, taking different types of food and tasting them, comparing the different varieties in that given food type
" Chocolate – milk chocolate, baker’s, semi-sweet, dark, cocoa powder
Nuts – almonds, cashews, peanuts, walnuts, pecans, hazelnuts"
http://legacy.sweetmarias.com/library/node/2931
And then there’s Sweet Maria’s guide, which is pretty detailed and fun to carry out, as well!
Hope this helps! Would love to hear if any one has any other guides or tips!