The infographic below was published by Copyblogger, a content marketing company known mostly for its online work with bloggers. It's for that audience, but at least nine of the items listed will apply to you as a songwriter.
For example, a "headline" is nothing more than a song title. The job is to get somebody's attention and provide an anchor that ties everything together.
The verse, since it's usually what people hear first, should weave a story so good that the listener will keep listening, wondering where you'll go next. As long as each line is great, he'll keep listening. Basically, everything in the "middle" of this infographic is about that -- keeping a reader (or listener) moving forward with you long enough for you to communicate your message.
And then what? Is the purpose of your song to have a big chorus people will want to sing along with? Do you want to make people feel something? Do you want listeners to get up and move? Should they be inspired to take action on something?
Whatever you want people do it, incorporate those "instructions" into your song through your writing. This is where you give them something they'll hold onto once the song is done and what will make you song successful.
So take a look at the elements below and consider them when writing (or re-writing) your next song. They will help.