I think the hardest part is being able to figure out how you feel about something, and then worrying about the language needed to mirror how you feel.
You have to learn how to use figurative language without it seeming obvious. There's no rule about this. A great writer can take any rule you might have and break it brilliantly, just for the joy of doing it, but it blends beautifully with the emotion.
The greatest poets develop all sorts of different ways of dealing with this problem and because they are so good at it, we hardly notice.
