I recently took part in an excellent on-line workshop run by Stephanie Dray of Maryland Romance Writers.
This inexpensive four-week long course explored a number of different approaches to plotting a novel. Although the workshop was particularly aimed at the romance genre, the principles applied to other genres too. I started out with a very basic idea, which might just about have made a short story, and this became amplified over the course of four weeks into a decent outline for a novel. I also rejigged my ‘Work in Progress’.
Although the course emphasised the use of Scrivener and Aeon Timeline, both being helpful software programs, the exercises could probably have been done on index cards or pieces of paper, as the emphasis was on thinking about characters, their motivations, and pivotal points in the plot structure. I have found that the planning and structuring particularly helps me as a part-time writer, making it easier to resume writing after a break.
They have more online workshops timetabled, so I shall be keeping an eye on their website.