I'm trans (female to male), and have been out to my friends for about two years now. I legally changed my name about a year and a half ago and have been on hormones for about a year.
I was a student when I came out, and both my friends and my classmates were very supportive. By contrast, my parents were fairly difficult - I tried to involve them in my transition by asking them to help choose my new name (and one of my middle names is what they'd have called me had I been born male), but they didn't want to be involved. They also refused to use my name and pronouns, despite knowing it upset me to be misgendered - and my dad went as far as wanting to write to the gender specialist I was seeing to "make him aware of our concerns [as your parents]". I hasten to add that I was 22 at the time!
I didn't tell them when I started hormones, partly because it's none of their business and partly because the changes were so gradual I hoped they'd realise over time (and, as it turns out, they have), I think living at the other end of the country has helped a great deal, since they're now much better about referring to me correctly. They're not as open about my transition as some other parents I know of - probably because I'm from a small town where there's still likely to be a degree of stigma.
That said, I'm definitely a lot happier since starting to transition. I'm now consistently being read as male, which is more important for me in alleviating dysphoria than surgery, and am about to be referred for a top surgery consultation (which will further cement my male gender since I'll be able to be shirtless like my cisgender male friends). I have a girlfriend of a year and a half, and we got together before I started medical transition. She identifies as straight and sees me as male like any other guy. We have an active and entirely satisfying sex life notwithstanding my lack of bottom surgery (for the unimaginative,
here's a handy flowchart).
I think the main thing I'd want people to know about trans people is that if you don't know their gender from how they're presenting,
please don't guess. There was a fair while where I dressed in a masculine manner but people could tell I was born female, so they'd call me "madam" and "she". It's perfectly acceptable to ask someone what their preferred pronouns are, or to refer to them as "they" until you know ("they" as the singular was the American Dialect Society's word of the year for 2015!). Similarly, if you think someone is using the "wrong" facilities for their gender, don't call them out on it - they know their identity better than you.
On a slightly unrelated note, whilst the media portrayal of trans people is improving (I particularly enjoyed the Women's Hour programme recently, with Jack Monroe and Lewis Hancox), I think it's still a little abridged at times. The general public has a tendency to fixate on the medical aspect of transition, rather than the social element. I think being trans is sometimes regarded as almost akin to an extreme form of "body modification", rather than a necessity to ensure that the outside is congruent with the individual's sense of self. The sooner we move away from the notion that gender is between the legs - when in reality it's between the ears (particularly for non-binary people!) the better.
I'm happy to answer any questions if there's anything more you'd like to ask.