When you see a post that looks like it belongs on LW, tell the author. This gets rid of a lot of the uncertainty about whether LW would appreciate it or whether it's too off-topic/speculative/whatever.
This. Being invited feels good.
Alternatively, if an author is not sure whether their article is a LW material, they can ask in the Open Thread.
Ever since Eliezer, Yvain, and myself stopped posting regularly, LW's front page has mostly been populated by meta posts. (The Discussion section is still abuzz with interesting content, though, including original research.)
Luckily, many LWers are posting potentially front-page-worthy content to their own blogs.
Below are some recent-ish highlights outside Less Wrong, for your reading enjoyment. I've added an * to my personal favorites.
Overcoming Bias (Robin Hanson, Rob Wiblin, Katja Grace, Carl Shulman)