For students that have hearing disabilities, create a lesson plan outline which will include a breakdown of all the points that will be made in the lesson with brief summaries. This gives the student a chance to go back and review anything they may have missed. These can be passed out to all students but will benefit those with hearing disabilities the most.
Buy a few hearing sound amplifiers. These can bought for about $10 a piece and will make a great addendum to your other teaching props. These are not made to replace hearing aids but help enhance sound for students that use hearing aids and tend to miss things here and there. The amplifiers will make sounds appear like they are closer then they actually are. They are designed to wear attached to the ear and are a one size fits all. You can pass them out at the start of class and collect them at the end.