I have been reading a lot of Bobby Owsinski's blogs. He posted this one recently:
http://bobbyowsinski.blogspot.com/2012/07/heres-whats-wrong-with-your-music.html I was very interested in the idea of groove. I guess they way I think of it is the element (or combination of elements) that make you want to move. If you were dancing to the music, what is it that makes you dance? If you're tapping on the desk, what is the rhythm and what is driving your finger tapping. I find it's often the rhythm parts, a lead hook, drums, vocals, everything really. Listened to a few songs I really like. M83 Midnight city for example. The main riff keeps you going. In the verses a simple synth staccato part subtly holds the groove. In maybe a hip hop or rap song it's about the vocals.
I hence went back to some of my music and listened. It's very easy for me to determine what holds the groove. But listening like this I can now hear "ok, that guitar part IS the groove, but the way I'm playing it doesn't really accentuate the groove. Those key groove elements are missing in my playing." Also as a song builds, another element is sometimes introduced which temporarily takes the groove. In those cases I know the previous holder needs to back off while the new part keeps you moving. A lot of my music I found the drums were NOT the groove. But in some sections they were. Sometimes the chorus drums, sometimes only the verse drums. Every song is different. Sometimes a simple drum fill fills in the groove in a blank spot. Everything has it's place and I see the importance of know what instrument (or vocal sometimes) is making you move. What makes you bop your head.
A few of my songs I notice in sections I really get into it and move. WHY? It's easy to hear when you look. Enhance that element. Don't make two conflicting grooves. It's confusing. It ruins it. Let them each have a turn if you need/want them both in a song.
Keeping in mind too that although one element may hold the groove, it doesn't necessarily mean it should be most prominent. It may subtly hold the groove in the background. Also doesn't mean it has to be upfront either. It could be anywhere in the 3D stereo depth sound stage. Every element has its place and this can change drastically from song to song and measure to measure even.
Anywho, I just saw this as a big eye opener for me and different way of thinking about your music. It stems right back to how you compose your parts, how you arrange them, how you play them, how you record them, how you mix them. Each step is so important. I can see compression (and the behaviour of different compressors) really making a big impact in enhancing the groove of a particular instrument. That and how you play it could be some key elements here.