Accessible forms of poetry for journaling? (opens in new tab)

I journal sporadically, and have sometimes wanted to record a thought as a poem. I like idea of using constraints to further my grasp on the thought I'm trying to express, and it'd leave me with something I'd feel proud to come back to. But I don't really know where to start? I'm hoping to find a form of poetry can be short enough to not feel daunting to start, but still forces enough structure to make the exercise worthwhile. I imagine this effort means I'll also need to read more poetry and...