My biggest problem with socks was that I'd make the last/first stitches on the needles too loose, no matter how much I seemed to tighten them.. This mostly felt like a problem when doing stockinette stitch, but it always showed a bit. I thought making heels would be difficult, but once I actually found a decent explanation (YouTube-videos!), it was pretty simple - both the "normal" one when going toe-down and the short-row heel or whatever it was when I knitted toe-up. The latter was way prettier, though, and I think I prefer toe-up anyways.
Switching from four needles to magic loop fixed the loose stitches, though - I still make the first stitch too loose, but the last stitch on the "other side" ends up being too tight, so they even each other out. And it felt way less awkward.
What's your favorite way to bind off socks when going toe-up? I've only tried two methods, and one of them (knit/slip one, knit one, pull the first over the recently knitted one, knit one, pull over..) always ends up being "too" tight (not unwearable or anything, just feels awkward), while the other one I tried was basically the same, but in pattern, and I managed to make one sock loose enough, but the other one ended up tight..
A couple of better (?) photos of the two most recent projects, both of which I'm pretty satisfied with - especially the socks, because I learned a lot and love the yarn:
(My summer hasn't included any knitting so far :/)