During the interview, do not fiddle with the tape recorder without a good reason. This ensures that what you have recorded cannot be erased. If you are using an outside microphone, keep it on a small stand. Do not handle the microphone while recording. If you are using an outside microphone, do not pass it back and forth.
Cassette tapes come in a case.
Keep the case. It protects the tape from dust. Never use the same tape for interviews with more than one person. Never use the same tape for more than one session of an interview with the same person. Check with your conference archive or the General Commission on Archives and History for example forms.