OK, since it's been on my mind a lot lately, I'll give it a shot.
Dysphoria to me is being uncomfortable in my own skin. It's a combination of several things.
First, there's self-loathing. I hate my male self. Hate to the point of avoiding mirrors, like some sort of trans-vampire.

Seriously, I don't like seeing my male genetalia to the point that in a bathroom remodel, I unconsciously selected cabinetry and mirror designs and placement such that I couldn't see below the waist when I moved between the dressing area and shower. I hate having facial hair. My hands start shaking when I have to bring the razor up to my face, and lean into the mirror to shave. I love going to electrolysis, where every zap makes me a little happier. (Oh, Freud would have a grand time with me...)
Second, there's the organic annoyance of having a brain that grew in utero in a high estrogen environment (probably DES, but there are so many ways we get formed) with female structure, trying to run in a high testosterone/low estrogen environment. There was a constant background irritation that I accomodated to, having known nothing else since age 15 when puberty was induced. It was perceived as a sense of "wrongness", a sort of background alarm that something wasn't right which was constantly present and eroding my confidence, promoting self-destructive behavior. Now that I'm on spiro, the inner calm that is so readily apparent when I'm meditating is remarkable. I've cried for joy at the relief this has brought me.
Third, there's gender identity and presentation. The cognitive dissonance of trying to be and present as someone other than who I am produces psychological stress.
Dysphoria is a sort of constant background state. I become more aware of and influenced by it when I encounter some specific reminder. My 'triggers' include seeing my male self in the mirror, shaving, and even being complemented on my appearance when presenting as male.
For a long time, the only way I had to alleviate the dysphoria was dressing to present as female. Bringing my gender presentation in line with my identity reduces the stress on me. The rush of euphoria drowns out much of the sense of "wrongness", and got me a few hours of peace. Now that I'm starting on HRT, that sense of wrongness is fading. I still have a strong drive to present as female, in line with my gender identity, just because I hate hiding myself and feel much more comfortable when I'm out.
I really don't know when it will disappear, but it has faded away a good bit. I suspect I won't be rid of it until after I'm full time and probably not til after gender confirmation surgery (GCS), should I make it that far.