I'm curious, guys.. as a rather serious question- let's say you had a particular sound or style a few years ago and you wanted to get back to that. How would you do it? Just listen to what you listened to back then? Take a break from songwriting?

Taking a break won’t necessarily get you back to a previous approach to music. It may in fact take you somewhere else. (nothing wrong with that either)
 
I think you cannot beat listening to what you did then and study it closely as to why it sounds the way it sounds.
 
I have just experienced this myself. After attending two Tangerine Dream gigs here live in Melbourne last week I started thinking about all the electronic music I used to compose and produce in the early 80's. The TD gigs reminded me of why I fell in love with them and started doing similar things. (I think being in close proximity to Edgar Froese had a profound effect on me a bit. If you love this sort of music, you cannot help being moved by him in some way)
 
Now I am listening to a lot of finished music as well as experiments I did between 1980 and 1984. That was an important period for me and it was a bit prolific too. I produced tons of music then. But great music that is at the very core of my being.  Hearing Tangerine Dream last week sort of smacked me a bit in the face and said hey Jeff this is what you do bro!  And well might I add.  Why aren't you doing it???
 
But we also want to progress and you don't want to be in one place forever either.  (Think about Miles Davis!!) But sometimes we stray as well from what we started out doing and we need to brought back into line at times too.

Jeff Evans
(I think being in close proximity to Edgar Froese had a profound effect on me a bit. If you love this sort of music, you cannot help being moved by him in some way)

 
I know how he infused soaring guitar into all those synths inspired me. 

Craig the second gig I saw for Tangerine Dream was in a small theatre and they played the soundtrack to the Sorcerer. (to the full length film might I add) I thought they were going to do the old Sorcerer but they have redone it all completely now and released a new double CD of that. They played the new Sorcerer soundtrack live.
 
Now there are lots of those soaring guitars in the old score and yes I loved them too. There was no guitarist live but they used a synth to do those sounds but I can tell you this, the soaring guitar sounds they had on the theatre gig were amazing to say the least.
 
They also added three Moog Voyagers and a Dave Smith Prophet 12 to the lineup though. Analog fatness extraordinaire!!!!!!!I nearly fell off my seat when they started playing the Voyagers! OMG! The PA in that room was something else too.
 
Sorry for getting off topic.

This is my first exposure to TD- they have a nice sound! Not so much what I consider to be a sort of 'corny 80's synth rock' sound but a lot more like a much better take on modern electronica.
 
Listening reminds me where my problem is- back to where I want to be, I was spending a lot of time listening to punk, alternative, and pop styles. More importantly though, I've lost any sort of spark I had; NOTHING inspires me at all, I have no desire to listen to anyone else's music (except jazz ._.) and I don't really want to/remember how to create my own stuff in my style. It' really hurts.
 
This past summer, I got heavily involved in jazz and big band, and since then I haven't been able to write ANYthing (except jazz)! I think listening to al that kind of music raised my needs for complexity or a certain sound to a point that I can't really tolerate anything else :'(
I'm thinking of just wiping my player of all the Miles Davis and Frank Sinatra and stuff and just putting some of my old favorites on there... TMBG, Bouncing Souls, Stelladeora, Owl City, Ben Folds
Or maybe just throw on Pandora radio!!

Record a Sex Pistols or Ramones cover.   (NOT in big band or jazz style...)

Hi David. Sorry for going off topic with Tangerine Dream. That is another thing although I appreciate you may be listening to and liking them too. They are a very classy form of electronic music. Interesting thing is they still are strong melody and chord wise. Their music is more complex than a lot of modern electronic music that is for sure.
 
I appreciate your Jazz situation too. Jazz can spoil you for melody over chords. It really is the ultimate art form in that regard. Way more complex than classical music even. If you listen to a lot of it then you tend to want to start writing that way.  I even studied a Jazz degree and immersed myself in it for 5 years and believe me I got into it. I studied it to learn the harmony not to be a Jazz musician at all.  My plan was to integrate Jazz and electronic music would you believe. Because these days most electronic music has zero harmony interest for me.  But many years later I am almost finding Jazz boring!! Hard to believe but true.
 
I think an important point here is really listen to what you like and really love and enjoy. No matter what that is. And pull it apart and work out why it is what it is. Become an expert on it. I have strayed a little myself and like I said in my first post, when I went to the Tangerine Dream concert it sort of hit me a bit thinking this is what I love and started doing back in 1980. Maybe I need to get back to it.  (or get back to the idea of bringing electronic music and Jazz harmony together)
 
If you are not sure what it is you love then you might have to listen to a lot of stuff until you get that internal emotional response. There is always some form of music that does something to us inside. This is hard to pin down now. Tangerine Dream certainly does it for me that is for sure.  They were seriously good live.
 

Go on a trip in a Volkswagen.
 
https://www.youtube.com/watch?v=x-G28iyPtz0
 
Backwards, not Forward. Somewhere in-between maybe.
 
Like anything, keep notes in a notebook, remember what you did in your brain, or come up with something similar when all else fails.
Get old, die, life goes on, planet goes on, the universe goes on.
Okay, back to reality.
 

It's hard to say much after a brief exposure to Tangerine Dream.  You almost need to be exposed to each decade, or even each five years of their over 40+ years of playing.  They've changed their style SOOOOO much over that time and yet I like just about everything they've done. 

That's actually very much how I feel about They Might Be Giants... they've ALWAYS had a particular quirky alternative rock style, but they've been able to sort of keep their overall sound concurrent. I love bands that last 20, 30, XX-years and change their sound for the better, you get to see a real evolution
 
I've been taking what I call "jazz rehab"... turned on the synth pop station on Pandora radio and chilled out for some hours. Got back my ability to listen to other music in about 2hrs, and ideas are already beginning to flow back in. :)