[grumpy_coder]

Yeah, I think the first mistake is thinking 'large software project' is specific enough to have any good advice at all.

Large software projects could include AAA console videogame, or banking mobile app, or embedded vehicle entertainment system, or airport baggage handling system, or hundreds of other totally different domains.

The only good advice I can think of is given a large software project try to hire someone (or a whole team) that have built something pretty similar before.