A lot of times I find a title for my poems by using a key phrase from somewhere inside the poem, a phrase that was mentioned or alluded to within the actual piece.
So the title is often directly related to the poem itself. For example, in my recent poem a merman’s love affair, the poem was about a man who had an affair, and the man’s wife was compared to a warrior mermaid. You can see the comparison within the poem’s phrase, “like a warrior mermaid.”
Since the piece was about the man’s affair and his wife was compared to a mermaid, I decided to call the man a “merman” since he was married to the “mermaid.” And that’s exactly where the title of the poem came from.
So I’ll often pull a few key phrases or ideas directly from a poem to use in the title. And sometimes I just pull an entire line from a poem and make that the title itself.
I hope that helped! :)
Best of luck.