Some words of advice from Steven Pinker about writing, in this interview with the Chronicle of Higher Education. I like the diagnosis:
First, academic writers start off with the wrong tacit goal. Rather than trying to show their readers something interesting in the world (what Francis-Noël Thomas and Mark Turner call "classic" style), their main goal is to prove that they are not naïve about how terribly difficult it is to assert anything about anything in their field (what they call "self-conscious," "ironic," or "postmodern" style). In that defensive stance, they clutter their prose with hedges, apologies, shudder quotes, narcissistic observations about their profession (as opposed to its subject matter), and metadiscourse (discourse about discourse).