General rules I currently try to follow (click on links for further discussion):
This article sheds light on why many are nervous to talk about race.
They are scared they may say something offensive.
Learning from this post can provide a lot of help to not be offensive.
Avoiding the topic of race, culture and ethnicity does not help move the country toward racial justice, dignity and respect.
Avoiding the topic of oppression keeps the oppression firmly in place.