If you've ever read the lyrics of a Simon and Garfunkle song, you read great poetry. If you want to write poems like that, start copying them. Let me explain.
Creativity is in many ways a myth. It's not that it doesn't exist, but that people's ideas about the creative process are misinformed. Many believe that to be creative is to invent something completely new. No artist or inventor out there has done this.
An individual had to write the first four-line verse or haiku poem, right? Is everyone that uses these forms now an uncreative copy-cat? Of course not. You have no choice but to copy forms, general ideas and techniques, so why not do so more systematically?
Find a poem you like, and play with the elements. Much of the beauty of some poems is in the structure and the rhythm. Try inserting your own words into that, just to see what happens.
Below is the last part of a poem titled "Gratitude." First it painted a picture of the beautiful mountains,and then...
Words fail, as they should...
So there is nothing to say
There is nothing to say
There is nothing
Look at the poem for a moment. If you take the general "gimmick" of the diminishing lines, you could insert all sorts of thoughts, couldn't you? An example of the top of my head:
Pain returns, as it must...
And to where can I turn for relief?
To where can I turn?
Where can I?
Except to life
Is this shameless? No more so than the second time a poet wrote a four-line verse. The new words have created a new poem, and in a longer poem, this copying of form for one verse might not even be noticed.
What is creativity if you don't create something? Use whatever tricks and techniques you need to start creating poetry.