A Sonnet??

Have you ever tried to write a sonnet?
It's not as easy as you might suppose.
One needs heaps of brains beneath his bonnet
To disguise meaning in the words composed.
In Iambic Pentameter pen your thoughts
On life, of love, of lust or things now lost;
Or acts one did not do or thinks he ought
Reminiscing or considering their cost.
In only fourteen lines it must be done
And they should never sound like simple runes,
But flow like a river ...not ramb'ling on.
Well-written sonnets sing like heav'ly tunes.
(This type of writing's a pain in the butt
I've tried hard but not made a good one yet)

Why can't I get this to work?