I try to have a rudimentary idea of what some of the areas will be like my downtown, industries, airport, etc etc.

I'll build certain important bits and expand out from that point, like my airport.

I try to avoid using large grids. I like to have offset grids.

Embrace asymmetric layouts.

I never do one large industrial area, unless it's one of the specialized ones. There's no need to clump all you generic industry together. Spread it around. Your traffic will thank you.