what’s the best way for a brand new user to organically grow on farcaster today? i have a friend who’s starting from near zero, and i found it difficult to recommend methods that didn’t require some pre-existing audience, and weren’t going to draw bots/farmers. any ideas?

In general, Farc is not a place where you should focus on getting people to subscribe. 
After all, if you are useful to the project, it gives you a badge and promotes your publications itself.

One way to do this is to interact with famous personalities.