Read your lyrics to yourself over and over and over and see if you start to sense a cadence to them. If they don't have a timing flow, look at other ways to say the same thing. And consider contractions if you have timing issues. If you have "can't" or "don't" somewhere and need another syllable, change to "can not" or "do not". Keep rhyming in mind and start thinking about rhyming patterns. You can rhyme the 1/2 and 3/4 AABB fashion, or 1/3 and 2/4 in ABAB. Once you feel that lyrical cadence the melody will come to you.

The main thing is telling the story in order. Just like you'd tell it sitting in a living room full of people. Just tell your story.