How to write a Valentine's Day love poem to your sweetie:
Don't mention obvious features -- her hair, his brawny shoulders. Mention some unexpected ones.
Mention oddly lovable traits, but not ones that will embarrass him/her too much,
If you're going to be erotic (a good thing if you really mean it) don't be too graphic. That just becomes embarrassing.
Don't try to make it rhyme -- love poem rhymes tend to be too obvious (arms/charms, love/stars above, etc.)
Don't end each line at the end of a sentence -- unexpected line breaks can give a poem a jolt of energy. Once you've finished your poem, go back and try breaking the lines different ways. Use your ear, use instinct, or be counterintuitive -- break the lines where your first instinct says they shouldn't be broken.
If you're inexperienced at writing poetry, find a model -- get some help. Take a poem with unexpected language and line breaks and make a pastiche of it, which means (at least as I use it) to start with imitating something else. then use that imitation as a springboard to find your own creativity. Improvise on it, changing words, adding your own personal touch, or just taking part of it and moving on from there to something that's old but new. It's not plagiarism if it's just for your darling, not for publication -- and if you credit the original author. If you do, you'll not only have a very special gift for your darling, the two of you can have a wonderful time going back to the original, and using it as a springboard to get into reading more poetry.
If you come up with a pastiche that you'd like to share, send it to me!