Start here http://www.authoritydirectory.com/blog/your-guide-to-starting-a-quality-directory/ And there are many other good articles to read about the topic on site
Try and plan out on paper as best you can every aspect of the directory you want to start. even if it's in mud format it's better than nothing, then continue to adjust your notes / site as you move forward and learn. stop and fix or edit any errors, and be prepared to work hard.
want to start with a new directory? want a free directory script or a paid one? provide some info that way we can point you in the right direction.
Well I really cant afford much right now so probally a free script. Now I also have NO programming skills.
in that case you could go for: idexu free script but it is limited to 100 listings or phpld they have a free script available or you could pick esyndicate they have a free version.