The-art-of-m, I’m impressed with your question!
From what I can see where I live, a lot of your contemporaries (not all) are not as interested in this as you are.
And I liked ihear’s answer. Like he said, complicated topic for a guy to post on, but I think he did a great job.
Easier for me to comment (not a guy!).
I would only add, keep your eyes open and look around you. As mentioned, tznius has a lot to do with not standing out. You’re not expected to dress like the Rav’s wife in Me’ah Shaarim if you live in LA. But find the people in your community that you have a connection with and look up to. And notice how they speak, walk, even wear their hair. No need to blot out every spark of individuality and buy exactly the same shoes or earrings! I’m sure you get the idea.
A man once told me, with regard to sifrei mussar, that his Rebbi IS a mussar Sefer!
I think the same can be said about some women whose behavior and manners can teach you more about tznius than a Sefer.
Good luck, and hope you don’t mind my posting when you asked for guys’ opinions!