Highlights:

1. Avoid all value judgments when writing up disciplinary action or termination letters; stick strictly to the facts. Embellishing the notes or communications with additional thoughts or opinions can't help and just might hurt a lot.
2. Always have HR present at termination-decision meetings. This way you get a witness to corroborate what is said, as well as help inexperienced managers avoid saying/doing something that is best left unsaid.
3. Always give about-to-be-fired employee at least a brief hearing. You don't want to be surprised later on, that for example, the employee had a FMLA or ADA problem you didn't know about.
4. And, document times 3. It is always disappointing to go back and find out that you did things the right way, but you have no records to prove it.

Lastly, The key is to look to a jury like a fair employer. If you follow that maxim in practice and on paper, you probably won't get hurt too badly if the discipline or termination action goes awry.