Our approach was: 1. Sketch mockups on paper, iterate until happy. 2. Sketch mockups in Photoshop, iterate until happy with every little detail. 3. Send photoshop mockups for slicing - get back HTML/CSS/JS 4. Convert static HTML files to static templates. In our case, it was Django templates. At this stage, we used dummy data so now the site would be served through django, exactly match the Photoshop images and the sliced HTML, data populated through views. That is, the static data is now hardcoded in the code rather than in the HTML. 5. Incrementally replace each view to serve data from DB instead of hardcoded. Data can be added to DB in Django using an interactive shell or using the admin interface. At this stage, we had our models flushed out and relationships between objects cleared up. 6. Add additional functionality such as forms and whatnot to actually accept input through the app. 7. Ajaxify everything to turn the website into a web app.

We didn't use any fancy tools beyond what's mentioned above.