A couple of months ago, I began using Trello while finishing my internship, and it impressed me so much that I began using it not only for weekly to-do lists, but also writing projects and even job searching. It's a wonderful and intuitive organizer and you can also using it for group projects too by sharing a board with other members. Basic service is free, but even then it's a very powerful tool.
If you have a lot on your writing plate, I strongly recommend thins, and in this post I'll show how it can help keep you focused on multiple things at once.
Here's my writing board on the site...
In Trello, you can make a number of boards, each one consisting of columns called lists and a number of tabs or cards in each list. I use one card per project or story. Each list helps organized by the kind of work being done, so I've got nonfiction and long and short fiction as well as a "Business" list for general housekeeping stuff and "Research" to help keep track of progress on the Document.
You'll notice that some cards have colored accents on them. Trello allows you to color-code cards, and I use this to tell at a glance what stage each project is. You can customize these labels in the sidebar to the right under "Menu."
Below are the different stages I assign to a project at any given time...
I don't know if this is included on other operating systems, but I use Yosemite on my MacBook Pro and it lets you tag files with different colors. I mention this because those are the same colors available to you in Trello. Personally, I find that very helpful because it lets me mark the projects directly based on their status.
If an project has been published, it has no color assigned to it because there's no additional work to do. Of course, sometimes stories can be reprinted or retired pieces can be polished off later for publication, which doesn't delete them (although you can permanently). Instead, archiving a card hides it in the sidebar to be retrieved later, making it a convenient vault for past work.
The cards aren't idle either. In fact, they have a lot of helpful features. Below is a card for a film review I'm working on for Carpe Nocturne...
The orange box contains the all-important due date or deadline, which can be edited on the right hand side. If you're withing twenty-four hours of your deadline, it'll turn yellow as a warning, and red if you're pass due. The green box contains the description in which I write the logline of the project I'm working on to quickly refresh my memory on the story. And the red box, which is a convenient way to track progress over time; so you can write a quick comment when you finish a draft, submit a piece, or hear back from a publisher. There's also the attachment button in the black box so you have the option of uploading and removing different drafts as you go along.
All in all, Trello is an amazing organizer, and once you make it part of your routine, I think you'll start wondering how you managed without it. Steve Dotto in Canada has a good demo for it on Youtube. And if you're part of a company that does a lot of collaborative work, I highly recommend the demo from Trello's developer Fog Creek Software.