Count and non-count nouns are difficult for ESL learners because in their native languages, they probably don’t have such things. For example, in Chinese, a noun is a noun; there’s no distinction between a countable noun and an uncountable noun. There’s no plural forms, and there are no definite articles “the” and indefinite articles “a/an.”
In English, you must be very careful, because the descriptive words or phrases that we use before a countable noun or an uncountable noun are sometimes different. We use “many” before a countable noun, but we must use “much” if the noun is uncountable. Also if it is uncountable, you cannot add “s” or “es” to the end of the word.
However, it is not always easy to tell if the word is countable or uncountable. Here are a few non-count nouns which ESL students often think are count nouns:
advice; equipment; mail; news; luggage; rice; cabbage; corn