Some people cannot identify nouns by memorizing definitions and lists. Some people can. A few common endings for nouns are shown below. For more noun suffixes, click here.
My favorite method for identifying nouns is to look at what each word is doing in a sentence. If I can put my, his, her, a, an, or the directly in front of the word and have my pair of words create an image in my mind, then I can identify the word as a noun. I must check to make sure my created pair does the same job as the word in the sentence. Many, many words have more than one job.
Please watch the video at http://www.youtube.com/watch?v=T7E9aonwQLY for further explanations.