These steps seem like they would worsen the breakup. However the world of relationships is not something that makes sense or follows logic. The time where you think you should call, you should not, and when you think you should be as emotive as a heartbroken poem, when you should be more stolid and steadfast.
The first step in fixing things is to accept that you need to break up. Time apart will show both of you how much you want to be together. Even more so, do not communicate, talk, call, send a heartbroken poem, nothing. This extremely hard step will serve to make coming back together even more powerful.
You should not wallow in self pity and sorrow. That leads to the heartbroken poem and song. You should be taking action. Making changes that fix your relationship should be your goal. You need to figure out what went wrong and change that part of your life. Otherwise you are set to stay apart.
It is your task to change and become better. It may seem easier or more appropriate to send a heartbroken poem to get back with the person you love. Romantic words and describing your feelings would seem like it should make things better. The intent is there, but it is likely to do more harm than good.
The reason for the failure of the heartbroken poem is that your ex-partner will likely read it the wrong way. It is full of emotion and heart and such power. Here you are, shipping this power to your ex as though it should change things will make your ex recoil. It will be taken as a form of emotional black mail, like you are going to win. This will only make your ex defensive and recoil away.
You will also seem like you are dismissing your ex and their needs. There might be real problems between you and your ex, which need to be addressed and taken care of. What you end up doing is writing a heartbroken poem hoping that it will solve everything. All you will do is add insult to injury.
The best thing you can do is to give space and address your problems yourself. Give plenty of space and try not to communicate. Should both of you address the problems that are plaguing your relationship, and you both make things such that the relationship can come back together, then and only then will things work out.
What seems like it should work, will not work. Things in a relationship do not follow logic or make sense. What should be done is to work on personal growth, instead of trying to fix your partner through talking, arguing, or sending the heartbroken poem.