Quick keys for converting points:
When in node tool, option click converts smooth nodes to sharp.
to convert sharp to smooth, press p to swap to pen tool, hover over the node until you get a little line icon rather than a cross and then click the sharp node you want to convert and pull out and it will swap back to smooth node...
here is a video to demonstrate
And to pull a handle out of a sharp node so that, whilst still sharp, the lines leaving the node are curved - pull the line next to the node until handles appear... to pop them back in again - option click the node...