First, let's talk about their interchangeability. There are some contexts where the two words could be used to mean "additional"; however, I think there seems to be a subtle difference in meaning when the word further is used:
The summit ended without any more talks.
The summit ended without any further talks.
I could not have run any further.
I could not have run any more.
In the case of the summit meeting, the word further hints that talks might have helped two sides come closer to an agreement. That's because one meaning of further is:
further (adv.) at or to a more advanced, successful, or desirable stage
(from NOAD)
In the case of the tired runner, any further suggests a greater distance, while any more suggests a longer time. While those meanings overlap, I think further might be a better word for a runner dropping out of a marathon, while more might be a better word for someone working out on a treadmill. That's because further also means:
further (adv.) by a greater distance, or for a longer way
(from NOAD)
As for the book, I think the best way to describe the latest edition of a book is:
a new edition of the book
You might use another when comparing two different editions of the same book:
I bought a new copy of A Study in Scarlet.
Really? I thought you already owned that book.
I do, but this was another edition.
It's harder to use further, because, in the context of publishing, I would interpret further to mean:
further (adj.) additional to what already exists or has already taken place or been done
(from NOAD)
However, I suppose we could:
The publisher has indicated a reluctance to print any further editions of this book.
In that last sentence, the adjectives new or more could work in place of further.
Best Answer
The easiest way for a native speaker to distinguish between a descriptive and classifier adjective is to attempt to intensify it. Consider the following:
While you can intensify descriptive adjectives (the very old train), you can't do it to classifiers, at least without some kind of strangeness.
Another test that can be applied is paraphrasing the noun phrase as a sentence that uses the verb be. In the example above, you can say the train is old, but not the train is steam.
You can also try to fit in another classifier before the one you're trying to test:
English doesn't allow for this type of structure if the adjective is descriptive. However, this is a one-way test only - you can't test whether something is a classifier because you can have a classifier followed by another:
Of course, this is less straightforward for a non-native speaker, who won't necessarily have that intuition that tells you whether a phrase is grammatical or not.
Some combination of the above is probably going to work for you, with the easiest being the intensifier.
For your specific example, let's apply some tests:
"an old political idea"
the political idea is old - descriptive
"latest educational reform"
The latest reform is educational - descriptive
"leather dancing shoes"
The dancing shoes are leather - descriptive
You can find out more by searching for epithet vs classifier tests, which produced some of the tests I've noted above.