The most important question when working with parents is not:

"How will I do?"

"What’s wrong with them?"

"Can I solve their problem?"

"Am I in the right frame of mind?"

"Is the room set up right?"

No, the important question is this:

"Do they trust me enough to work with me?"

Their trust is determined by how well you can satisfy these questions or doubts in parents’ minds: 

1."Can I believe you?"  This is essentially about your honesty and transparency.

2."Are you acting in the best interests of my child?" This is essentially reassuring them that it’s not about you.

3."Do you know what you are talking about?" This is about being credible so you need to do your homework about their child.

Earn trust, earn trust, earn trust and the rest will take care of itself.