Creating an R package can be a daunting task if you have only used R interactively, in notebooks or scripts. This talk will demystify the process creation process by going from a simple R script and turning it into a fully fledged package complete with documentation, README, examples and tests all in only twenty minutes! Along the way you will be introduced to useful functions for package development from the devtools and usethis packages, as well as the best places to find information about package development.
http://www.rstudio.com/resources/videos/you-can-make-a-package-in-20-minutes/