Teaching aids are tools that teachers use in the classroom to improve learning. There are three main categories: audio aids like radios, visual aids like pictures and charts, and audio-visual aids that combine both like videos. Some common teaching aids discussed are flip charts for group learning, models to demonstrate real objects, graphs to visualize data, and interactive whiteboards for multimedia lessons and presentations. Effective use of teaching aids engages more senses, saves time, and helps students recall and understand lessons better.