If you are trying to organise your life, perhaps as a New Year's resolution, you are probably looking for a multi-platform task managing service; one that's not so complicated that it gets in the way of the actual tasks and is relatively simple to use. I have the app that's just for you.
Producteev allows you to add tasks to different workspaces. It lets you add priority, tags and deadlines to tasks along with the person responsible for the task in case you are working in a team. You can also add more detailed notes to tasks if you wish.
Producteev has a lovely UI which is easy to navigate and get used to. All the hard work is done in the background by the app - the usual synchronising of tasks and whatnot.
Apps are available for Android, iOS, Mac and PC. Head over to the Producteev website for further information and links to the various applications.