Starting with others: I suppose we sub-consciously mis-gender when presented with behaviour we perceive as being 'male' is exhibited by a trans-woman. It's an unusual phenomenon and one that presumably all of us experience now and again - in that we appear to have an innate gendering system within us. Why? It makes absolutely no sense, but does provide an explanation for our gender crazed society. It's worse in Europe - according to the French even tables and croissants and the Eiffel Tower have genders!!! To an English speaker well versed in 'the' it makes no sense. It's a dichotomy: on this side of the channel Melissa types on her gender neutral laptop; across a few miles of ocean Melanie types on her male computer. Yet both were made in the same factory in China.
Melanie, who can't speak English very well, has no understanding of why objects shouldn't be gendered. Melissa, who can't speak French (so will let the funky music do the talking, love Girls Aloud!!!), has no grasp of why they should be.
And we do the same thing with people. Except we do it worse. 'Le' and 'La', as metaphor. Melissa did 'La Baking of La Cupcakes then went in the shed and did Le Engineering with Le Tools'. Ignore the inherent sexism, because that's irritating, in fact don't. We're conditioned to attach gender norms to particular activities through social construction. Girls get twin-sets, boys get train-sets. Whatever.
Those on the trans spectrum have it a little different. A non-trans person (woman, otherwise I have to write everything twice and my nails are bad enough already) does a 'Le' thing. I don't know what, something really 'Le'. That doesn't, in the eyes of anyone else, make her less of a woman. She's just doing what society has reserved as male. Essentially we can't reduce that; she may be viewed as expressing a male behaviour, but no-one can say she's doing that because she's actually a man. Or used to be.
The danger we have is the second stage of reduction, in that a trans-woman does a 'Le' thing and it's seen as an expression (externally) of the man she used to be. Or in many cases never was. I'd like to offer a solution - except I think it's something that's pushed deep within us. The only way round it is to stop focussing so much on gendering activities and things. Which would be beneficial to society, women, everyone really. The way out of this is greater sexual and gender equality - I dream of the day when girls and boys do whatever they like without the fear of being labelled as sissies or tomboys or whatever. By extension that sort of functional feminism is important to trans people. It'll be the thing that stops the reduction I mentioned earlier.
However it's part of our conditioning, and I have done it myself. Sorry! But I just have. People do it, I suppose, less with me as my interests are somewhat stereotypically feminine and in some ways I do alter my behaviour to emphasise that. For instance I'm far less likely to be misgendered if my afternoon consists of coffee with girlfriends than if it's, I don't know, going to something that men like. Errm, steam trains? They seem to love steam trains. I digress.
Essentially we need to stop speaking French and start speaking English when it comes to our activities. 'The' is a lovely word.

As for myself..... Hmmm.

I have a past, a present (sort of a hiatus) and a future as the true me. Yet. What about the past and how to think of myself. I've managed to think in almost gender neutral terms of what happened in those scant years, dappled by long waned moons and tied together with unspooled cassette tape # Nineties Baby!!!
I think of myself, back then, as a number of semi-fictional constructs used by Melissa in order to serve her needs at the time. They weren't strong, well liked or even particularly convincing. Instead they were little white lies she told in order to keep going.
It's like: Ellen Ripley kills some aliens. Did Sigourney Weaver kill any aliens? No, it was a fiction. But only a semi-fiction for Sigourney because she was actually there. She has the real memory of going on set, in character, and possibly even believing she was holding a real, working ray-gun. It's worse with obsessive-level characters. I've heard a radio interview with Nichelle Nichols that sort of summed this up. She played Uhura in Star Trek (never seen it really) and was famous for, amongst other things, the first televised inter-racial kiss. The interviewer asked her how it felt to kiss William Shatner. Her response was: "I didn't kiss Will, Uhura kissed Captain Kirk". I don't have any interest in Star Trek, but something in her response struck a chord. I'd find out why years later.
What Nichelle did, nicely, was to touch on the weird interface of an event being a fiction and a reality at the same time. It happened, their mouths physically touched, yet the emotion that drove it came from the make-believe realm.
Which kind of sums up how I used to be. Uhura lives in the minds of many, as does my male presentation. Fewer people have met Nichelle, but she's the truth of the situation. She can make Uhura do things, same as I can make him do things, but she isn't Uhura in the same way I'm not him. The two identities exist concurrently. I just can't wait to hang up my suit jacket for the last time. I guess in the same way she was happy to slip out of sixties high-camp nylon!!