I started a one-person software company 18 months ago with no outside investment. Revenue and profits are healthy ($100K+/year), expenses are low.
Although I am not actively seeking to sell, if the right buyer came along at the right price, I'd certainly consider selling.
What is a good strategy for making this known to the right people?
You could post something about it on a well-known Q&A site for entrepreneurs. That might help.
Wait, hang on....
If you don't care whether you sell or not, your best "strategy on the side" is to just become as well-known as possible, which of course is probably part of your strategy anyway.
For example, I sold my company to someone who saw our ad in a magazine. Sometimes finding the buyer is as simple as that.
If you do decide to "go out and sell," that's completely different. Lots of great advice on the VentureHacks blog. It helps to have active partnerships already (they often buy you) and you want to "blitz" for selling, not stretch it out over time, to increase the chance of having more than one buyer, which is typically how you get the best valuation.