Sure, you've got your Day Planner® and your iCal® and your pads of paper strewn about the office, but have you considered taking your "to-do" list electronic? There are lots of great options for this and lots of reasons it might make sense for you to have a to-do list online and on your iPhone, 'Berry, or other palm device (you can't misplace the electronic list, for one thing, you can set reminders for yourself for another, and it leaves your calendar for appointments only, giving you a better picture of how you're spending your time).
There are tons of options, so I'll begin with my favorite few and add from there. If any of them sound interesting or helpful, give 'em a try. You have nothing to lose... anymore.
My current list-making app in "heavy rotation" is Nozbe, and here is a screen shot of my own system, right NOW:
Highlight Reel: I can organize items by Project, by Project Label ("tags" to you and me) or "Contexts," or, where the list item needs to take place. I can upload documents (not viewable online, but can be downloaded again later), can access Nozbe through a dedicated iPhone app as well, AND can link to my Evernote account (and we LOVE Evernote!). I can also "share" items here with selected workmates, but, really, I use Nozbe just in a desperate bid to keep myself organized (and use other project software/cloudware for those team projects). There's lots more, so go here: Nozbe Visual Tour
Or watch the first intro video here:
This video will show you how the system works (it's easy). Like most things online, there is a free version and a version that is more robust that costs. Figure out what works for you, and get organized!