Pronouns
I use they/them pronouns, for example:
They went to the park.
I went with them.
They brought their frisbee.
At least I think it was theirs.
They threw the frisbee to themself.
These pronouns are the correct way to refer to me in third-person, and as such are not “preferred”. Avoiding their use, as recommended by some outdated style guides, is disrespectful.
If clarification is required, a parenthetical or footnote stating that I use they/them pronouns is fine, for example “Ryan uses they/them pronouns”. There is no need to say I’m non-binary.
Gender
I’m non-binary, specifically an androgyne, and am transgender. My gender expression is ambiguously neutral. Most of the time I dress in casual jeans with a geeky fitted t-shirt, keep my hair long, and don’t wear makeup. My nails are often painted, usually with elaborate art.
Sex
Although I’m not intersex, my body has a non-standard combination of traditionally feminine and masculine physical characteristics. This has been accomplished through combination of hormone replacement therapy and surgery.
Other Terminology and Framing
Where a title is absolutely required, “Mx” (pronounced “MUKS”) is acceptable.
Referring to me as an “enby”[1] is fine, but please be aware that some non-binary people don’t like the term.
My gender has never “changed”. I’ve always been non-binary. The only thing that’s ever changed is accepting it, living it openly, and altering my body.
I should not be described as “identifying as” non-binary. This phrasing, while somewhat common, can imply someone’s gender is abnormal or not real. In fact, unless it is relevant, I would prefer my gender not be mentioned at all.
GLAAD has a media reference which goes into more detail on some of these issues.
The Nonbinary Wiki has a fairly extensive page covering gender-neutral language in English which may be helpful.