The television writing process tends to go like this:
1. Outline - a rough, two page-ish breakdown of what the proposed series is about, the main characters, some brief episode ideas.
2. Treatment - assuming the outline gets commissioned, the treatment is around ten pages, with much more detail on the main characters, a proper breakdown of what the first episode will contain, almost on a scene by scene basis, and a good half page-ish on the other episodes. Treatments are actually much more work than might initially appear, because there's usually a lot of negotiation and back and forth with the producer/script editor, and often big chunks of time spent hanging around while you wait to hear if you've got the commission for the next stage. The next stage being...
3. First draft - the fun bit. Mainly because this is where you get to write dialogue, which writers like because it fills lots of space on the page. If you've done the treatment properly, you don't even have to worry about what scenes happen in what order, and who's in them, because you've already done all that! Hurrah! Now you can just have your characters say clever funny things to each other, with the occasional bit of action.
4. Rewrites. This usually involves taking out most of the clever funny things and putting in more action.
The best way to work is to have a number of projects on the go (well, duh) all at slightly different stages. Probably one thing at script level, where you're trying to write five pages or so a day, a couple of treatments when you can airily write 'and character A gets out of the scene by saying something pithy and amusing' without having to actually come up with something, you know, pithy and amusing, and then a few ideas that might just exist on the single paragraph level (or less), waiting to be turned into treatments. So you can jot down 'The OC, only with werewolves!!!!!' and feel like you've done a morning's work.
At the moment, however, I'm working on four different treatments. Which could bode well for the latter half of this year if all the things get commissioned, but is currently boding quite badly for my bank balance, because a treatment only tends to get you about ten per cent of what you'd get for the first draft, even though, for reasons described above, the first draft is actually much less intensive and more fun.
It's also hard keeping your mind fixed on one project and not drifting on to another, particularly when you're running actually quite an intense D&D campaign on Monday nights. Hence my current plan for Gino the barman from Hotel Babylon to be drafted in on an escort quest to take the body of a deceased gray dwarf astronomer on a perilous journey through the Underdark so the last rites can be given on a underground bridge above a portal to the Elemental Plane of Fire.
Would make a good episode though.