While teaching articles in English seems easy, there are some tricky aspects to keep in mind, especially for those struggling to master English as a second language. Pointing out the difference between definite and indefinite articles is a good starting place; after that, teaching the few easily understandable rules that govern article usage is usually best accomplished by some simple memorization activities and opportunities to practice both orally and in a variety of writing exercises.
The Definite Article
Point out that "the" is what is called a definite article, meaning that it is used to refer to a specific item that has previously been determined. For example, if you ask for "the peach," you are asking for a certain peach you already know of; however, if you were to ask for "a peach," it could be any of a number of them sitting on the counter.
Spend some time examining which geography-based proper nouns take a definite article and which do not. It takes some practice to learn that cities, when used alone, do not. For example, we would say, simply, Detroit and Columbus, in contrast to "the cities of Detroit and Columbus." Compare "in America" to "in the United States." Regional areas often use "the," as in "the Southwest."
Give students examples of how "the" is omitted altogether with certain nouns; these nouns generally have to be learned through memorization. For example, the words for "soccer" and other sports, the word "people," and names of school subjects such as "chemistry," along with some other nouns, generally are not proceeded by "the" except in certain circumstances.
The Indefinite Article
Explain that the indefinite articles "a" and "an" are used to refer to any one of a number of items rather than one specific item. Notice the difference in these two statements: "I have a solution" and "I have the solution." Similarly, "I want an agenda" and "I want the agenda."
Use verbal practice to distinguish between the use of "a" and "an," since it is only the sound that counts when deciding which article to use. Beginning letters give a clue, but it is actually how the word is pronounced that counts. Use the following sentence using the letter "h" as an example: "I'll ride a horse for an hour."
Practice appropriate article selection by using the exercises listed in the resources below. Once students have mastered these, the next step would be to work on composing original sentences using articles correctly.