Half Asleep updated quickly because I sat down and wrote it veeeery slowly over the course of six months before I started posting. It was all done and ready to be polished by the time posting began. Plus, it was a Big Bang fic, so I kind of had a fire lit under my ass for it. :P

It could be time management, or it could be that you're like George RR Martin. He's a famously slow writer of a famously good fantasy series who, afaik, writes when he knows he's going to put out quality work.