Since it's I^2*R, you have to size your wires according to max sustained current, take into account thermal conductivity of where your wires are placed and keep all contacts tight. Also size circuit breakers according to that max current so they trip before the whole thing catastrophically overheats. Which is a trivial exersize in itself.

Short-to-case and leak current protection (the reason for three-wire systems/PE conductors and differential protection) takes second place. In larger installations there are also considerations about grounding / ground loops, but that usually does not matter for residential.

This is what the most of the code should be about (I never read US ones, but was doing apartments/small homes for like 20 years already).

The rest, as in colors, sleeves and exact connectors used is helpful, but not critical, and if you think that a typical contractor would not botch it up in a most horrible way, well..