Great thread! I fluctuate a bit, but I'm more or less a 16, at my largest I was a 22 and at my smallest a 14. I'm trying to get down to a 10-12, any smaller wouldn't look right on me, I don't think (I have a large build - broad shoulders, thick fingers, etc).
As far as clothes go, I dress like it's my JOB. I feel like it's my duty as a plus-size girl to not look dowdy, frumpy, or like I'm ashamed of my body when I'm out in public. I usually wear dresses and sometimes skinny jeans. Most of my dresses and tops come from Anthropologie - a lot of their dresses are available up to a size 14, and many of them have elastic waists so that they hug your body at your thinnest part. I also buy trapeze dresses at normal-size shops and belt them at my waist so that they're fitted exactly where I need them to be - I've got Ella Moss, Rachel Pally, Vince, all kinds of dresses that aren't supposed to fit me). My skinnies are all from Old Navy, and if you choose carefully, you can find them in washes that look very high end (I've had multiple regular-size girls ask me what brand they were, expecting them to be designer). I also pay a lot of attention to my handbags (naturally) and jewelry in order to look put together - hey, accessories always fit!
I actually never shop in plus-only shops. I find those clothes to almost always be incredibly unflattering on my body, they're always cut too big and blousey and long for me. I also try to edit myself very seriously when shopping, I don't buy things to try and follow friends unless they're very flattering as well.