That's the trick. You really can't. If you do the research you find that, on the left and the right, "neoconservative" tends to mean whatever the writer wants it to mean. Like "fascist" and many other terms, the concept in common use has been diluted to the point where the word has no working meaning any more. It has devolved mostly into an all-purpose insult that allows people to avoid painful things like abstract principles and policies. You might notice that it gets applied to people with widely varying philosophies and principles. They can't ALL be "neoconservatives."

Sometimes it's used to separate foreign policy political realists from political idealists. Weirdly, I've seen both sides defined as "neocons." By some people on the far right and far left, it's just used as a shorthand for "The Jews."

You can find articles and papers that delve into the history of the movement--and I'd bet money most people who use the term wouldn't know Strauss from a hole in the ground--but when you get down to it, the word has left any historical reality far behind. It's like being one of those libertarians who still insists on using the term "liberal" in the classic sense.

It's pretty much a more sophisticated version of "boogerhead" at this point.