If you've had a run-in with a parent? Document.
If you've had an uncomfortable talk with your supervisor? Document.
If you have an incident with a student? Document.
When in doubt? Document.
Documentation is very simple. Just remember to record the who, what, where, when, why and how and try to be as unemotional in your description as possible. Do not make judgements or accusations of the others involved. Simply tell your side of the story. Be concrete and use as simple language as you can. Save your documentation in such a way that you can access it at all times- even if you can't get to school.
Also remember that you have a right to representation in any administrative meeting, but, unlike Miranda rights, you have to ask for it. If an administrator requires you to attend a meeting, you must or risk being insubordinate. If that is the case, you are within your rights to say, "I'd be happy to discuss this matter further once I have union representation."