Lyrically, 'less words mean more' is a pretty good rule of thumb. Try to cut out the fat and get to the meat of what you're saying.
I don't try to approach things any differently, songwriting-wise, regardless of what I'm doing. I try to write whatever the best thing is that I'm doing that day. If I'm working on a pop song, I'm working on a pop song to the best of my ability. If I'm working on a bluegrass song, it's the same thing. They're not really different parts of the brain.
