I think the best way to familiarize oneself with The New Sincerity is to identify certain examples of well-known New Sinceritists, so I put together this handy illustrated chart.
To make it easier to define The New Sincerity, I've provided contrasting types for each example, which we'll call Old Sincerity and Fake Sincerity.
Think of Old Sincerity as very similar to New Sincerity, except that Old Sinceritists haven't had to pass through or react against postmodern irony the way New Sinceritists have. Typically, this means Old Sinceritists are from an older generation, but not necessarily. There are many instances of Old Sinceritists who are actually younger than New Sinceritists, but for some reason grew up without any capacity for irony whatsoever.
While Fake Sincerity sounds like a pejorative label, I don't intend it as such. There are actually plenty of Fake Sinceritists whose work I greatly enjoy. I call them Fake Sinceritists only because, while for various reasons they may appear to be Old or New Sinceritists, they are in fact either subtle or highly advanced Ironists, or in some cases, complete phonies.
I've done my best to come up with appropriate examples for these categories, but when it comes to The New Sincerity, there is much room for error and differing definitions. Please feel free to provide your own examples, or argue like a goofy pain in the ass about the correctness of my choices, in the comments.