CMA of recent sales and listings.
Traffic counts if you are in an undesirable location.
Lot values if your lot is less desirable than others.
Pictures that show conditions of the houses and that yours is in worse shape than others.
Can be lots of reasons yours is less valuable than others in the neighborhood, you just need to take documented proof to the appraiser and a good argument. Could be every house in the neighborhood is new and yours is 50 years old? Could be everyone has 3 car and you have 2, or everyone has a pool and you don't. Things like that.
Good luck and let us know what works for you and if you get your value lowered.
I presume you are talking to one of the appraisers on this visit. Whatever deal he offers you, you have the right to demand a hearing in front of a panel if you don't like his offer.