Flashcards are excellent tools to teach ESL classes of all levels.
They are simple to use and you can use them to present or review vocabulary, grammar topics, practice pronunciation, play games, get your students to make sentences, or write stories.
how to use flashcards?
You can create your own flashcard with cut-outs from magazines, photos you can find online. Or have your students make them as a task when practicing vocabulary or any grammar topic.
Another good thing about flashcards is that once you create them, they can be reused with different groups of students for different topics to teach ESL classes.