Rimshot
iPhone voice recorder because I commute to work every day. If I don't capture the idea, it's gone.
I also have a template setup for a vocal mic, piano, acoustic or electric guitar. 
I will start messing around with nothing in mind until something interests me.
I have lots of takes that were not played to a metronome.
I put the date in the song title and go back to listen at times.
At this point, I have more ideas waiting to become songs than not.
 
Once I get a new song idea started, I will start building the chords to a basic drum track. I will sing melody over it but without any meaningful lyrics. In fact, I will substitute actual words with guttural sounds - anything to just be a placeholder.
 
Then, as the song takes shape, I will start writing lyrics to the melody. Lyrics take the longest for me. I might work on them for weeks/months. Not in a hurry so it doesn't matter. 
Once that is all done, I start working on the arrangement of all the parts. That takes less time because I am not that good on guitar and I tend to except my playing too quickly. I have found great use of Melodyne to help me with the gross imperfections of some of my work. 
 
When all of that is done, I start mixing. That can take weeks and weeks. I am never happy with the first batch of them. My studio, headphones, iPhone, and car all tell me something different. It is all a compromise at this point. At this point, I don't have anyone to answer too but my fellow forum songwriters and myself. There was a time in my life where it all really mattered with publishing deals, album deals, filmscoring, etc. Those were the days when you did not have the opportunity of working on something over and over again for months at a time. Then, when you recorded, you had to commit to tape and move on again. Now, I have all this technology to help me. I don't take any of it for granted. 
 

Jimmy,
 
This is exactly the way I song write.  Lyrics take the longest and are the hardest for me to finish.  I am always searching for a better phrase.  I also use the iPhone to quickly jot down notes.  Most of the time, it seems to be while driving or some place that I can not get to paper to jot them down.  

I had a Technics turntable once.
 
I later wished I had another one and microphone.
 

Talk is cheap , just write a song and post it ...
if you don't want to post it fine  ...go hide it where every you choose to keep it safe  .
 
Kenny

Interesting chat on it all.....yeah Kenny....imagine what we ain't heard from Prince yet....supposedly a load locked up in that vault...
 I got loads of ideas on phones(sim cards) 'n MC7 now ...some taking shape as songs though only a few that are almost to completion.   Time is fleeting in these busy summer months....much to do this fall to catch up....but I get my pick'n moments as I can and trying to keep the "songs" moving along ....  ;o)

Mesh

Midiboy
 
 
What are some of your favorite song writing techniques? 

Beer

Mesh this isn't a good idea.  That used to be my strategery as well.  

eph221

Mesh

Midiboy
 
 
What are some of your favorite song writing techniques? 

Beer

Mesh this isn't a good idea.  That used to be my strategery as well.  

Yeah, best to move up to better drugs. 

timidi
My best technique is taking a shower or a walk.
 

It really is amazing how often things come to me in the shower.

Pitter patter Pitter patter....bam bam bam......
....shower jamz ....or in the rain   ....always rockin   ;o) 
 Seriously though my best lyric moments are when I first wake up very early....before I even want/need to .... ideas based on first thoughts as I come outta the am dream phase of sleep...and if I don't jot it (on phone)down...no way I would remember it .  Now it's just puttin them sucka's to the right tunes  ... ;o)
 
 

I defiantly feel like the odd man out here not being a guitar player.
 
When I get ideas for a song (piece of music) I write it down on paper, I am a paper and pencil (pen) sort of guy, always have since I was 12 years old. So my flow is Paper > Sibelius > Sonar.
 
Also a lot (most?) my music does not make use of vertical structures based on thirds (chords). My music is very horizontal in conception, any vertical structures that occur are a result of the horizontal lines or a thickening of the line.
 
Ed

I like writing songs even tho I don't play any instrument very well.

I have RealGuitar  play one of its basic picking patterns to a 4 measure chord sequence.
I have another track for the melody part, usually a steel guitar. I insert notes in PRV view (with the mouse) until something interesting happens and build on that.
After a whole lot of evolving changes (including the RealGuitar pattern) I can come up with a pretty good song, IMO.

It's all MIDI tho, not that there's anything wrong with that. Lately I've been learning how to play the melody line on a real electric guitar which enables much better articulations.