I come from a Russian (OCA) parish, and this is what I do.
Our tradition has us chant on the same tone, so pick your conversational pitch and use it. Then, loosen your tummy, and breathe into it; as you breathe out, your lower diaphram will push your sound out stronger. Lastly, remember to not crane your neck, and to make sure your mouth is wide open without straining.
All this together should make a Trevor Trumpet.