Congratulations on the start of your house building.
One thing i would say is take plenty of pictures at all stages of the build, when we built the builder tried to charge us an extra $1400 for extra concrete needed for the slab, this was 11 weeks after they poured the slab.
They tried to say that the trenches collapsed prior to pouring the concrete due to rain, fourtunatly we had taken loads of pictured and proved that this was not the case and the fact that there was no rain for the whole month that the concrete was poured, they backed down in the end.
One more thing, as i paint new builds check what quality paint you are getting when you do your selections as most builders only provide 2 coats of the cheapest paint as standard and you will find that its not very good and once marked will not clean, i always give the owner a chance to upgrade to 3 coats and finish in a top quality paint. The builder will charge you quite a bit for this or you can take a chance and see if the painter that does your house can upgrade you on the side.
good luck with it all.
kevin