What advice would you give to someone seeking to develop a devotional relationship with Antinous?

The sine qua non for a relationship with Antinous, in my opinion, is having an image of him upon which to focus one's devotional attentions. This can be almost anything: a picture from a book or the cover of a book, a postcard, one of the coin replicas available for sale depicting him, an actual bust or statue replica, something you create yourself or that another artist has made, or simply the photo of your favorite depiction of him on your computer screen. (The most definitive and complete collection of these is available at http://www.antinoos.info/.) While there are apophatic dimensions to his devotion at various points, this is a cultus that dwells best in the realms of imagery and sensual detail, and because Antinous was a very specific person whose image and likeness is known with a great deal of certainty, using those images as focal points for our contact with him (and his contact with us!) is very useful.

Begin to see the eyes and ears and mouth of these images as the eyes and ears and mouth of Antinous. Honor the god through the image in whatever way you feel is most appropriate. Sing him hymns, speak your prayers aloud to him. Antinous has never been claimed as an omniscient deity, and thus he cannot hear your silent thoughts or look into your heart and see your intentions; you must speak them aloud. He can even intercede for you on behalf of other gods, particularly those to whom he was syncretized, or with whom he had some relation—the Egyptian gods Thoth, Re-Harakhte, and Hapi fall into the latter category, for example. And, apart from that, start keeping your senses sharp for where he may appear in your life to inspire you or communicate with you in your daily activities, particularly in dreams, where he will often turn up (and has done so from the earliest times of his cultus). One of the epithets Antinous shares with Dionysos is Epiphanes, "he who comes/arrives," and so being prepared for unexpected epiphanies is a good thing to keep in mind when engaging in a cultic relationship to this particular god.

I know that there were hero cults within ancient religions, particularly within Hellenic and Roman faiths. Does that play a significant part in contemporary Roman or Hellenic Pagan worship? In your opinion, should it?

I have seen precious little indication of modern interest in hero cultus within Hellenic and Roman practices, which is sad, though I also freely admit that I'm also not much a part of mainstream Hellenic or Roman Pagan practices. Herakles/Hercules is often worshipped as a god in the modern period, but he was one of these liminal figures, who was both a hero and a god. Achilleus, on the other hand, is generally not worshipped as a hero, despite ample evidence of such in the ancient world; read Philostratus's Heroikos if in doubt! Much of this goes back to what I said above about the worry that worshipping mortals is somehow "wrong," I think; but there is also the common confusion of what it means to have hero cultus or hero-worship.

Ancient hero-worship is not screaming in line at the cinema over Robert Pattinson or idolizing Justin Bieber...though, note, the terminology is often rather similar (e.g. "idolize"). The objects of hero cultus were considered heroes or heroines because of what they did and the virtues they upheld in their lives; they were not utter perfection, in the way that Christian saints are often said to be, but they served an important function for their devotees or the communities that were indebted to them as founders or saviors. A good way to think of heroes within hero cultus is as a particularly important class of deified ancestors, the mightiest of the mighty dead one might even say. They are often people without whom one cannot imagine doing what one is doing now.