Choose level-appropriate testing materials. Recordings are more helpful than video because your students won't have the context and body language of a movie or TV show to help with comprehension. Bring in as many outside listening activities as possible, whether they are recordings as part of the language-learning curriculum, authentic materials such as podcasts or radio shows, or guest speakers. Your students will get used to your voice and may fall into a comfort zone. To effectively assess their practical English listening skills, you need to see how well they understand various speakers.
Give your students a specific task. Avoid giving general directions such as to listen and summarize what they hear or just get a general idea of what is happening. Ask a few specific questions about the recording for them to anticipate and listen to. You can do this in a multiple-choice or true/false format. When they have answered the questions, give the correct answers and then replay the recording for the students to listen specifically for the answer. If you find that a certain question is answered incorrectly by most of the students, this will give you some guidance about what your students need help with and what you need to spend more time covering.
Expose your students to accents. You must prepare your students to understand speakers with foreign and regional accents. English is an international language, meaning your students may come into contact with speakers who have multiple linguistic backgrounds. Whether your students are immigrants integrating into a new community of English speakers or looking to do international business or professional work with English speakers, they will need to communicate with people who have a variety of accents. You can find listening exercise and assessment materials that specifically include accented English.
Use music to assess listening skills within various contexts. Music is a good way for students to have fun and take a break from standard curriculum while perfecting their listening. Tell your students the name of a song and have them make predictions about what it is about. Follow the song with a discussion about the predictions and then replay it.