Well, I'm playing (and watching) SC2 again.
I'm still Plat Tier 2, which means that I guess I don't suck all that horribly. I played a ton of games against the Elite AI to get back into some good habits, but what really helped me get back into it was watching streams.
I've been watching a bunch of streams that I think are really good:
Neuro (Zerg)
PiG (all races)
Winter (all races)
Neuro has a lot of Zerg-specific instructional stuff, in addition to streaming his games. He seems to take a calmer approach to instruction.
PiG is probably the best player amongst the streamers listed above. I believe he played pro for awhile, and he's given instruction to the other two streamers (I think), in addition to having some detailed videos and coaching for all levels of players, of all races.
I must admit that I mainly watch Winter for amusement. He's got some good content, but a lot of what he streams is ANGRY COACH, and stuff like that, which makes it harder to find instructional content.