There are only 2 ways I find the bikes I really like (1890s-1950
1) the equivalent of Craigslist in my area; 2) other bike collectors.
For #2, my "strategy" has been to run my line of credit into the stratosphere, and buy lottery tickets weekly (do you think I'm joking?).
For #1, I search multiple times per day. If I see something I really want at a reasonable price, I promise the seller their full asking price and ask them to hold it for me 'till I can get there. Sometimes I overpay for something that wasn't as good as the photos, but I keep my word to pay what I said I would pay if the seller didn't misrepresent the bike. The bad deals balance out in the end with the nice finds.
Regarding a question in an earlier post about what you consider a "score", if it's a rare and valuable bike at a low price that you want, then it all comes down to 2 things: the seller doesn't know what they have; and you beat all the other guys to get there first. Be patient, you may only get one or two such scores every ten years.
One last point. I have a couple of bikes from the '40s to '60s that are spectacular. They look like they just came off the bike shop floor new. What I did in each case was buy 2 really good original, identical bikes from the same assembly line, and take the best parts from each and put them together. Then I sold the one with the remaining parts. I'm talking about $100 bikes here. I did it for fun and to keep them for myself, not to resell. I don't want anyone to think I'm in the Frankenbike business.
Good luck!