Org-mode is great. Org is this super-task management package that merges outlining and structured document editing abilities with task management glue. It sounds like a weird combination at first, when you realize that it means that you can effectively do work and organize your work in the same set of files without needing to "switch modes," between a planning/task list interface and a "doing things" interface, the effects are amazing.
I'll leave "the awesomeness org-mode" to other people and other posts, and spend time here focusing on why "org-mode is awesome but won't do your work for you," and "if you're new to org-mode you will probably want to do things in a certain way, but don't" issues. Org-mode is great and it can be even better if you avoid developing a few bad habits.
Use `org-capture <http://orgmode.org/manual/Capture.html>`_ as much as possible. Org-capture is a quick interface within emacs that lets you open a temporary buffer, take a few notes, and save the notes into a file. It has advanced features for more complex data entry features and data types. The temptation is to use it as a "quick entry" tool for task list items, but don't just use it to capture new tasks. Capture links and bookmarks, store notes and important information, If org-mode is your outboard emacs-based brain, then org-capture is it's main input device. Fighting it, means that your org files end up being less useful.
Avoid using org-mode as a simple task list, and particularly avoid constructing the content in your org files to "game" your agenda view. The agenda compiles a working task list for your actionable notes, working backwards from this means your notes are less than useful things can get lost and all of the really cool things that org lets you do aren't accessible to you.
This may just be the application of a good general information management practice, but: distribute information evenly throughout all levels of the organizational hierarchy of the file. Use the org-narrow-to-subtree function to focus your current work on a specific portion of a file, and don't bury information or have it sitting around in one big unorganized pile.
Hope this helps!