When I acquired various .Org domains, years ago, I always FIRST thought of their development potential . . meaning "Some day I'd like to / I hope to develop this domain . . ". Unfortunately, life sometimes gets in the way of the best plans.
. . so . . I have an interesting domain portfolio . . and there's only so many hours in the day . . and there's bills to pay . . so I've sold a few .Org domains along the way.
I've never been eager to sell but I've accepted some decent offers, from entities / executives that saw a domain's "value in use" = the domain's inherent messaging value (typically one word industry defining domains, all generics, no trademarks, etc). Like many others I don't report my domain sales. Whatever ego I have in the domain world it's tempered by the realities of business, specifically self-employment, which is largely about managing cash flow. I've been self-employed (professionally and in the WebDev / domain spaces) for 30+ years. It takes a certain skill set to make that happen.
So . . my $.02 . .
1) Don't count on getting rich on 2 word .Org domains, even if they're laden with valuable keywords. There are often multiple domain reg' options in the 2 word realm . . but only one, one word industry defining domain-word option. Still, there's some interesting two word versions in certain instances. The required skill is identifying what separates desirable from junk. That's a lesson for another day.
2) I don't view .Org domains with the same mind that I view .Com domains. It's not simply "investment thinking". It's development thinking, i.e., can I add value to the domain . . can I improve my cash flow . . and not do anything that will impair the domain's value to potential suitors who believe they can domain more with the Web-address. My acquisition outlook has always been "industry defining" thinking, preferably one-word industry defining domains - such as packaging as an industry, manufacturing as an industry, tourism, trade, investing, export, etc. Such domains are not easy to come by today . . but . . if you do your homework . . and are patient . . and . .
3) When it comes to selling take a look at the $$$$$$$ being spent by industry Orgs and NPOs on marketing, brand development and messaging . . and top level salaries in the C-suite of such industry's orgs. Some spend million$ on marketing / building their presence. Just because an entity holds itself out as a non-profit that does not mean it cannot afford a domain that will save that entity $$$$$$$ on future branding / messaging / identity costs. In many instances, especially as the world continues its move to all digital / all the time, the right domain-identity will pay for itself, over and over.
4) IF you are planning to play in this space you will do yourself a favor to look at pricing in the aftermarket. Markets are not always efficient when it comes to pricing . . and there are times . . and "times in the market" . . when there are buying opportunities . . if you are holding cash in reserve for such moments, when others are selling. This will require the ability to sift through MANY domains QUICKLY with a FOCUS on "commercial grade" domains.
Like most things in the domain world it's most often wiser / smarter / the better move to acquire one really good domain - for $1,000+ - than 100 newly reg'ed "lottery ticket" domains for $1,000+. Once you spend your $1000.+ for that one domain you will only need to pay 1 annual renewal fee. The other approach - buying 100+ marginal domains - will cost you that same $1000+ each and every year . . and that is why SO many who have played or have recently started playing in the domaining space fail. So, if you only have $100 or $200 or whatever to spend . . buy the very best .Org or .Com you can find.
FWIW, many of the bigger ticket domain sales are not reported . . so don't think the reported sales set the market. Also, don't rely on domain appraisal tools for anything other than baseline thinking. Those appraisal tools rely, heavily, on reported sales data. You got that?
In summary, save up your money and then pick one or two .Org domains, preferably ones that are mis-priced in the aftermarket, preferably ones that are industry defining, and that you wouldn't mind or would enjoy developing . . while remaining open to suitors.
Finally, it's better to be smart than lucky . . but I'll never be off-put by a bit of luck.