First of all, it was an honor to see one of my shots come up when I looked at the three photographs you used as your examples. Thank you.(posted 8123 days ago)As for my advice, just take that 70s rangefinder (whatever it may be), load it with some Tri-X and go out and shoot.
For what it's worth, I try to meter off of something "general" in the area I'm shooting and then preset the focus for a distance I'm feeling comfortable with that day, and shoot. The hardest part for me is not feeling "obtrusive." Somedays I feel invisible, other days I feel like everyone within a hyndred yards is staring at me.
Good luck, enjoy, and post some results.
David