Here’s a handy slideshow with most of the LGBTQIA+ identities you’ll ever hear or see. View the speaker notes for more details and info sources.
When others talk about their experiences as members of the LGBTQIA+ community, be sure to listen. Just because someone’s stories may differ from what you expect does not change their validity. Homophobia and transphobia are deeply rooted in society, and everyone faces them in different ways.
Transgender and gender-nonconforming people often pick a name and pronouns that differ from the ones assigned to them at birth. Pronouns are the gendered words used to refer to somebody in the third person (e.g. when talking about somebody, not to them); she/her/hers or he/him/his are the two most common sets of pronouns, typically for female and male identifying people, respectively. However, somebody may not use the pronouns you expect them to, or use pronouns outside of the gender binary such as the gender-neutral they/them/theirs, or neopronouns like xe/xem/xir.
If somebody introduces or refers to themselves with a name and pronouns, use them, even if they differ from other names/pronouns you may have previously known. Pay attention to the pronouns used to refer to a person and respect their preferences, even when they are not in the room. When speaking hypothetically, or about somebody of unknown gender, stick to they/them/theirs rather than “he or she”, as gender neutral language is the most inclusive and respectful. And remember, it’s okay to make mistakes - nobody blames you for slipping up on a new name or set of pronouns every now and again. The important part is to make an effort to learn and correct yourself.
For most people, including lots of queer people, the LGBTQIA+ community is an uncharted territory. There are a lot of terms and concepts that are confusing, and most people don’t formally learn their definitions and have only a vague idea of what it means to belong to the community. The most vital step in allyship is acknowledging your ignorance and overcoming it. It’s okay to not know what something means; it’s not okay to make assumptions and act in harmful ways out of ignorance.
Education about the LGBTQIA+ community can come from a variety of sources. For some, it may be a literal class on gender and sexuality - the humanities department at IIT offers a few different LGBT-focused classes, which can be a useful elective for those wishing to learn in a formal setting. Less formally, plenty of online sources can provide definitions and explain concepts; be careful to view sources curated by queer people, though, as homophobic and transphobic biases warp understandings of the community. However, the LGBTQIA+ community is diverse and ever-changing, and lots of terms used in decades past are now considered outdated. Wherever you turn for information about the queer community, be mindful of conflicting perspectives and evolving terminology.