If there's one sure way to miss a deadline, it's to completely forget about it. If you have a complicated schedule with lots of deadlines, meetings and projects going on, it's essential that you keep a calendar with all your deadline dates on it. Even if your schedule isn't that busy, you still need a place where you can record vital deadlines. A desk or wall calendar will do the trick, and there are lots of productivity software packages that will help you track important dates. Your cell phone or smartphone probably has a calendar function as well, so you'll always have it with you. You can also keep track of important dates via your work e-mail service.
The more elaborate productivity software also lets you organize other information with the calendar. You can keep the names and contact info for the other people working on the project with you, record any research you do regarding your project, or even maintain folders of important files and documents.