Valuations - What should I include for best valuation?

I just went through this process so might be able to offer my (very limited) experience.

The valuation for my build was done in two parts: Land and house.

The land is straight forward: Its whatever you paid for the land. List price and thats it. Simple.
The house price is your total contract price in your build contract. So this will include your siteworks/BAL as its something you have to pay the builder for to get a dwelling on the property. Everything outside of what you paid to get the land, basically.

I am certainly no expert on valuations but on reading our report they look at things like your layout with how many rooms and how big the overall house is, the fixtures and the quality of them, as well as what hasn't been included in your build contract (so if you were going to do aircon and painting after handover it is noted and taken into account that the house isn't quite 100% finished if its not painted).

I think the things to keep in mind for valuation issues are to ensure that you aren't paying too much for things and that you can get a reasonably priced build complete. Little luxuries that can be changed out later are things I'd drop. Aircon can be done later and simply (assuming single story) and would add $10k to your build but not increase valuation by as much. Gold plated taps and door handles or whatever might be nice but can really add up so maybe do them after handover. You can't easily change the benchtop in the kitchen without major work so if you want to get a nicer stone slab through the builder then I say go for it.
The house as it is with some improvements shouldn't cause you valuation issues from a volume builder I'd think. They'll be building dozens of them so they'll know what they can put in and at what price, with some wiggle room for people to make changes.