For my webcomics, I serve as both writer and editor. The writing part is something most people understand - I come up with a plot, write a script, and give it to the artist to pen the pages. It's the role of editor that most people don't understand.
The basic way to view it as I'm like a traffic controller, managing all aspects of the comic's creation. When the story is written, I get it to the artist right away. Then I approve the artist's rough pencil layouts, sometimes making suggestions on how the page is going to look. There may be something important that needs shown that I know will show up later in the story. After I give a final thumbs up, the artist gets started on the final pencils. Then I get it to the inker, then to the colorist, and finally to the letterer.
All along the way, I have to make sure each creator is getting paid for their work, based on established page rates and a contract that we've negotiated and signed. Each member of the team is due compensation for the work they've done. It helps me in that I get quality creators, and it helps them by giving them a professional credit as they build their resume and work toward achieving more in their comics careers.
Today was a good example of me spending time as an editor. I got the final page of art for issue 1 of The Rift, and I promptly got the final 4-page installment to the letterer. I also talked with my artist for The Rift to see about his interest in continuing to work future issues. For ClosetWorld, I received the final inked page 1 of installment 4, so I sent it to the colorist. And I communicated with my ClosetWorld colorist about his payment for a previous installment.
The trick when being a writer and an editor is not to get so bogged down in editorial work that you forget to spend time writing. This means constantly looking ahead, making sure that installments are written ahead of time, so when the artist is done, he's getting the next installment. This is money in their pockets, and for many of them, they factor that payment into their monthly budget. I don't want to be the one that holds that up, so I'm always looking ahead, making sure I've got a script ready for them.
It's a juggling act, but if you love comics as much as I do, every step is worth it. It's certainly worth it when you see the pages come in and your vision comes to life. There's no greater feeling in comics than to see the final letters completed and the comic being released, hopefully for others to enjoy.