My face honestly just seemed to melt away.
Now, to be fair, I was very overweight pre-transition, so the effects were probably a lot more pronounced than in others, but seriously, it's hard to even recognize myself.
Pre-transition, my face had a lot of muscle in it... and I don't mean strong muscle, I just mean subtle muscles that added to the bulk of it. I had a MUCH bigger and stronger-looking jaw, my brow muscles I believe were a bit bigger because they always seemed very "heavy" looking which gave me a very large-looking forehead, my nose looked a bit more bulbous, and my chin and neck were SO much bigger it's not even funny.
Basically it was almost like all of this bulk slowly melted away. My chin stopped looking huge, although now it looks a bit pointier, my brows melted down to the bone a bit, so they honestly just don't look as powerful as before, my cheeks gradually and slowly started getting rounder, but the biggest change of all was in skin texture. My skin was very oily, pore-heavy, olive-colored, and thick pre-hormones. As time has gotten on, the color has lightened significantly, more "rosiness" has come out (presumably because the skin is thinner and thus the blood vessels are more visible,) it REALLY thinned out, and started looking much smoother. (I still have big pores for a girl, but it's much better than it was.) Also, because the bulk was trimmed down, my eyes got a lot less squished, and looked more open. These were all wonderful changes. On a downside to this reduction in bulk, though, it did make my face look a little bit more angular. My chin, although not as bulky, looks a bit pointier now. So does my nose. That happens. As the bulk melts off, the bones can become a bit more prominent.
Another huge change was the cheeks. They started getting rounder and rounder, and have kept filling in continuously for like the last 2 years straight. Basically the apples of the cheeks got bigger. More and more fat filling in there, even as I've been losing weight. And this really didn't take off until the middle of my 2nd year on HRT. It's one of the last and biggest changes that happens to your face, and it's one of the most feminizing. And yeah, it takes time. HRT can actually make your face look more angular in the first year to year and a half, but then slowly it will start filling in and smoothing and rounding out. Patience is definitely required there.
Long hair also did a number in feminizing my face. Especially once my bangs got long enough to cover my temples. I have a bit of a big forehead, so having that diagonal line to break up my forehead's squareness was a big help.
And as someone else said, I added a smile.