I use Mx. as both my courtesy title and my honorific. (I pronounce it like "mix", but I've heard "em-ex" too and think that also sounds nice.)
I refer to myself with grammatically neuter terms when possible (person, sibling), including cases where a masculine or feminine term is also used neutrally (master, hero, witch, cow, not that I am any of those things).
I refer to myself with feminine terms in cases where a binary grammatical gender is required (principally in other languages, but occasionally with English words like auntorprincess, not that I am either of those things). I still try to find neuter options when available in binary-gendered languages, but not when they'd go against the language's norms (kabbalat mitzvah, not the anglicized b'mitzvah).
When talking about myself pre-transition, I usually (but not always) do so in the masculine and with my birth name.
And if you wouldn't like to refer to me that way, that's fine too. What is gender but the product of how you see me? If you see me as a he and a man, or a she and a woman, or as a transsexual, or as a femboy, then by all means. By picking a word, you make it the correct one, at least for that moment, at least for you and me.
One exception: If you find yourself writing about me in mainspace, then for the purposes of MOS:GENDERID, my requested pronouns are those of the article's most recent editor. This can be automated with code such as {{ucfirst:{{they are|{{REVISIONUSER}}}}}} widely considered the worst administrator in Wikipedia history.
