Well, I'm not sure I can get a column out of techniques for revision or collaboration, because honestly there's not a lot to say about either unless I start making stuff up, but I can talk about them here a little bit.
There's this thing I say to people, over and over again, at conventions and workshops, until it stops having any meaning at all. If there were one piece of artistic advice I could leave the world, it would be this:
There are no rules. There are only techniques that work or don't work.
If you are a writer, people are going to try to sell you their books of rules. Some of these people may be the ones who make their living writing how-to-write books. Some of them may be successful authors who have discovered a set of techniques that work for them. Some of them may be opinionated blowhards, like myself.
Don't listen to any of them.
See, here's the thing. The only thing that matters about what you're doing is whether it works. If it doesn't work, then the only thing that matters it is either fixing it, or doing enough else right that it doesn't matter than you got some things wrong.
Storytelling is too hard--and to subjective--to do perfectly. There will always be trade-offs, things you sacrifice for other things. And there will always be things that aren't important to some writers--and readers--that are important to others.
So, I was asked about my revising process. I've talked about it in detail here before, with examples, and I'm honestly not sure how useful it is to anyone to go over it again. Besically, revising is the process of identifying the parts that don't work and fixing them as best you can--on a sentence level, on a paragraph level, on a meta level, on a story structure level. You fix the prose and the characterization and the plot and the theme, remove stray bits, add linking bits. Make sure the structure works. Take out or fix the confusing parts.
Some people have very careful and precise processes they go through for this work. (Holly Lisle has an essay on her site about her one-pass revision process.)
I don't. I do all sorts of things you aren't supposed to do: I revise as I go. I stop in the middle and go back and restructure the first third of the book. I write out of order. I revise out of order. When I do my final revision passes, I do them any which way. When I find something broken, I either fix it, or I leave myself a note to fix it later.
I suspect the question really is, how do you identify something broken? And that's a hard one.
The only answer I know is "experience."
The other question was, how do you collaborate?
And well, you just do. You write something and when you get bored or stuck, you send it to your collaborator. And they revise what you wrote and write their own bit, and when they get bored or stuck they send it to you. And you revise their revision and their new contribution and then write the next bit--
Until you have a story.
And while you are doing this you fire a bunch of emails back and forth brainstorming and sharing your brilliant ideas, and if you disagree about something, one of you caves.
And when you have a complete story, you do a few more revision passes and send it out.
I dunno. Does it have to be more complicated than that?