My songwriting technique is:-
1. Think up a really good tune in my head.
2. Improvise random words and nonsense so I'm not humming along.
3. Write down this improv as the lyrics, assuring myself I will return later and write better lyrics.
4. Come back two weeks later, decide those lyrics are fine.
5. Fin.
I think the benefit of my style of lyric writing is that if it is truly terrible, I'll just come back and think up new verses on the fly, and repeat until I have something competent. It's become a recurring habit of having a really good song with absolute crap for lyrics, and just sitting on it for about a year. Then, at 5am one night, picking up my guitar and knocking off a really decent set of lyrics for it in about 10 minutes.