It's more than just creating a rhyme. It's a mental picture or a feeling...from you.
The Beatles had many great songs. Some of the quieter ones were the most artful, in my opinion. Listen to 'In My Life' or 'Yesterday'. Impactful lyrics and they transport you to a feeling.
Even if you want to just send a cool vibe, Joe Elliot from Def Leppard used to say that their lyrics were 'deep and meaningless'. I think he was getting at, that the songs sell a vibe and not an actual story.
An example I wrote (and I think posted here at one time or another). I've had a song in my head that tells about something very personal. If I tell the story literally, it has no impact. It has to represent how I feel and not the story itself. Here's an example of some of the lyrics:
There's beauty in desolation
Comfort in desperation
It's not enough to lay here and just pray
But today, you're far, far away
You may not know exactly what the story was but it should at least give you the idea that it's a loss and it hurts.
The point being, spend time understanding what it is that you want to say. Then forget about the exact words that tell the story. Explain how you feel. Write down how you feel. Maybe with your song, do some image association. Think not about the days wasting away but what were those wasted days like? Were the autumn days with cool breezes and falling leaves? Do the leaves fall down like the days from your past? You know..make it a picture that someone can relate to.
