There's a handful of us on the site who work with him to some degree or another.
As said above, one good method of getting his attention is to pray to him or otherwise to reach out and express that you are interested in some kind of contact with him. There is not a real formal spell or ritual or method to get in touch.
You could always set up an offering for him when expressing your desire for contact. If you'd like to read more about what offerings to him could be seen as appropriate: