HCAD Hearing — How to Prep?

We bought our house two years ago. HCAD thinks it's now worth 60% more so we filed an appeal. Long story short, we now have a hearing.

In theory it should be a pretty easy win. We have the information from our house purchase, and most of the comparables they used for our house don't account for the fact that we're a townhouse with a tiny yard and not a typical single family home.

What can I prepare? Can I put together a powerpoint? Other supporting docs?