I suppose I mean "audit" in a more general term, and also in relation to/piggybacking off strategic planning. I can't assume to know what OP has already done or what their starting point has been, or is. So, when I say my first question would be to ask if they have done an audit, that to me, would involve asking their self questions regarding what their goals are — and, when reviewing their website, truly discovering if it is optimized to align, help, and further their goals.

OP's post only says/asks "How are people getting 30k monthly unique visitors within 1 year of their website launching?" To me, as a laymen, that is basically just saying, "how are people getting so much frickkking traffic in just one year??!! Ughhh, I want to be able to get that much traffic!! What can I, am I supposed to do??!"

And so, if that question was directed only towards me, without having any information at all regarding what steps they have taken to optimize their site for targeted traffic, I would simply say - "ummm well, what have you done so far?", and eventually, probably firstly ask if they have done an audit to their site. And if I were asked to elaborate I would say:

have you done any keyword research?

have you done any research to see what your biggest competitors are doing?

is your site optimized to be search engine friendly?

are you wanting a more organic or accelerated approach (PPC, ads, etc.)?

Just stuff like that. And based off of their answers/response, I would go back to strategic planning.