Gender 101:
Gender identity is, for many, a rather new concept. The more it is studied, the more often what seemed like "simple common sense" is simply inaccurate, rude, or even hurtful. Here are a few links to what one might call "primers" for those seeking to get up to speed.
The Gender Book - "The GENDER books is a fun, colorful, community-based resource, which illustrates the beautiful diversity of gender - a gender 101 for anyone and everyone."
Gender Identity - The REAL Sex Talk This is an extremely well-produced and easy to consume vido primer on gender identity, terminology, etiquette, etc.
Beauty and Fashion
Miscellaneous Useful Stuff:
A message from a Christian mother of a trans child
Transgender and Non-Binary People FAQ - Human Rights Campaign
Gender Development Program | Children's National (childrensnational.org)
Gender Spectrum Homepage - Gender Spectrum
The National Center for Transgender Equality
The World Professional Association for Transgender Health - Standards of Care