When I teach poetry-writing, I sometimes invite students to make lists of their favorite words--favorite chiefly because how they sound or intuitively "feel" to the writer, and favorite (secondarily) because of some personal connection to or memory about the word. I advise the students not to include too many words that they like simply because of a concept the word represents, like "freedom," unless the sound appeals, too. But of course I don't "prohibit" such words.
Such a list is useful in itself, but then you can also begin to work toward a poem by stringing some of the words together--going from specific language (with no subject in mind yet) toward a subject--and there's no rush.
Here's a link to a poem I read for Youtube, one made up of some of my favorite words; it's just a list poem, with "of" thrown in a lot as a kind of binding agent, mortar: