While Bit and Bill offer good "artistic" advice, let me demure a bit. Songwriting is both an art AND a craft. Most everybody can easily get the "art" part as that means, on a practical, self-evident basis that you can write whatever the heck you want no matter how self referential or obtuse. And if you don't give a flying frack about anyone who might listen to your magnum opus, and what their takeaway is to it...then proceed on, Sun Ra.
BUT...if you care what others both think of and connect to when listening to your noodlins...then take care and use the CRAFT side of songwriting diligently.
Make sense. Have each new line advance the line that came before it. Have an interesting story to tell. And...and this is very important whether you like it or not...if possible put a "twist" in at the end. Yes...people...even ol curmudgeons...like that. Even though later, on reflection, they might feel a bit of self loathing because they do.
And...most importantly...be friggin concise. If you have to explain your lyrics WITH your lyrics...you have already lost the battle. Both with yourself, and the listener.
Listen to Randy Newman. Listen to John Hiatt. Lennon/McCartney. Lieber/Stoller. Hoagy Carmichael. Steven Sondheim. The list goes on.
And here's one last bit of windbag advice: write about concepts and not occurrences. Unless the occurances represent concepts.
In short...get out of your own tiny head and into the heads of everyone else.
Just my 2 cents.