Mike Schmitz did a fantastic job of teaching us the Getting Things Done philosophy in his three part series. In those tutorials, he concentrated on using OmniFocus as the task manager. Whilst OmniFocus is a great task manager, it's extremely powerful and may be overkill for some people.
If you'd still like to try out some GTD principals, why not use an alternative task manager to OmniFocus called Wunderlist.
Wunderlist is cross platform with free apps for iOS, Mac, (and Windows, Android, Windows Phone, Amazon Kindle Fire and even Chromebooks!)
In this tutorial, Allison Sheridan will teach how to to use this fantastic tool, keep your action items synced across all of your Mac and iOS devices, how to share to-do lists, and even assign action items to other people.