From an agent's point of view, I'd guess that any collaborative writing you do now is likely to be with another newbie - unless a friend of yours is a career writer who wants you to write with them, no professional writer is likely to agree to collaborate with a beginner (I'm using that word to differentiate, though obviously you're not a "beginner" as such).
An agent won't touch you until you can demonstrate that you can put together a decent script - simply having good ideas is unlikely to be enough. A lot of agents do read unsolicited scripts, in the UK at least, but you'll probably have to slog through a lot of submissions before you get the kind of response you're after.
Avoid adaptations - there are always going to be copyright issues, and they don't demonstrate as clearly your ability to come up with original ideas and stories.
If you're part of any kind of writing group or community, the best thing to do is search it for people who you think you could work well with, then try tossing some ideas around. Make sure any collaborator is at least as enthusiastic as you are, and serious about making it.
― Markelby (Mark C), Tuesday, 9 March 2004 14:03 (twenty-one years ago)