The next question, “How do I know if a noun is countable or uncountable?”, is similarly not easy to answer!
We’re speaking about English, remember?
It’s time to take out our dictionaries – hard-bound, soft-bound, or electronic. 
We will be using an online version, from Longman’s Dictionary of American English.
We’ll begin with an easy noun: the noun, advice. You can click on the hyperlink or you can see below:
This noun has one definition, and right away the dictionary listing says [uncountable].
That was easy. So now we know that this noun has NO plural form and that the verb we use should be in a singular form. We also know to NOT use an article (a and an) before this noun.
So how do we count this noun, then? How do we quantify it? Look at the example “a piece/word of advice“. This would be the standard way of counting items of advice.
Just yesterday a friend offered me some advice that I did not solicit. I said to her, “Did I ask you for advice?” She said “No” and that part of the conversation ended, and the topic was changed. Thus, grammatically, you see there was no article (a or an) used before the noun, which is correct for an uncountable noun.
Be sure, with looking up any word, in particular a noncountable noun, to see if the dictionary gives you any suggestions for how to quantify this noun.
We’ll stop here for today, at this easy place.
