DO use normal mouth movements and speak in a normal tone of voice. DO remember to include the deaf person in everything - even minor details, especially when plans are changed. DON'T decide what the deaf person needs to know or doesn't need to know. DO write as much as possible.
Many words look exactly the same on the mouth.
DO demonstrate how things are done. DON'T let more than one person talk at a time and let the deaf person know who is speaking. DO be aware that there is a time lag between the time a hearing person says something and the time when the deaf person gets the information from the interpreter. DON'T think the deaf person is not smart or the interpreter is not skilled because of the time lag. It takes time to translate from one language to another.