Some poets use numbers, while some avoid titles altogether. However, a title always has the potential to be a useful part of the whole.
A student recently asked for some tips, which I synthesized here.
None—this gives a sense of acceleration, getting in to the poem quickly. It is like entering a house without a foyer or mudroom. It loses the technique of title, but it can have a clean immediate feeling.
First line—the title functions as a first line or intro to the poem. This is a way to add a line to a poem–particularly in a fixed form.
Contrast—the title sets up an expectation that it fulfills (13 Ways of Looking At A Blackbird by Wallace Stevens or any list poem) or contradicts the opening in an interesting way.
Painterly—an imagistic title that might go with a work of art. This is among my favorite options–descriptive, associative.
Explanatory, but only in a poetic sense—don’t summarize as an editorial (A Private Calligraphy—a poem of mine about knitting in Japan)
From the form—don’t just call a poem “Sestina” but Adrienne Rich has “Blue Ghazals.”
Obviously rules are made to be broken, but this gives some options. I’d be delighted to have you share your own process as well