Some tips when writing a org in Emacs

The table of contents includes all headlines in the document. If you need to use a different depth, or turn it off entirely, set the org-export-with-toc variable accordingly. You can achieve the same on a per file basis, using the following 'toc' item in 'OPTIONS' keyword:

#+OPTION: toc:2     (only include two levels in TOC)
#+OPTION: toc:nil   (no default TOC at all)

You can make words 'bold', 'italic', '_underlined_', 'verbatim' and 'code', and, if you must, 'strike-through'.

You can use LaTeX-like syntax to insert special symbols - named entities - like 'α' to indicate the Greek letter, or '→' to indicate an arrow. Completion for these symbols is available, just type '\' and maybe a few letters, and press M-TAB to see possible completions. If you need such a symbol inside a word, terminate it with a pair of curly brackets. For example:

Pro tip: Given a circle Γ of diameter d, the length of its circumference is πd.