Смотрим структуру и ее соблюдаем.
В общем по верстке:
app == Final point
| css = CSS output
| fonts = fonts
| img = img destination
| js = JS output folder
| vendor - JS plugins, directly connected to project
src == Source files
| jade - HTML sources
| js = JS working folder
| org - Structure-organization files
| part - JS parts for concatenation
| plugin - Plugins for concatenation, output in app/js/plugins.js
| less = LESS sources
| 3l - LESS mixins framework
"grunt" (without options) - watch task, compiles jade, js and LESS on change
"grunt build" - build all project files