My previous theme was done with the thematic framework. This time, for more fine control, I decided to adapt the default twentyten theme for my purposes instead. Just in case the theme gets updated with something cool in future, I decided to make the theme a child theme.
Thus the first thing to do was to create the style.css file with the theme name and parent theme name in the comments. Once that was done, I could then start modifying and adding on to the theme to suit my purposes.