* Edit the help file skeletons in 'man', possibly combining help files for multiple functions.
* Edit the exports in 'NAMESPACE', and add necessary imports.
* Put any C/C++/Fortran code in 'src'.
* If you have compiled code, add a useDynLib() directive to 'NAMESPACE'.
* Run R CMD build to build the package tarball.
* Run R CMD check to check the package tarball.

Read "Writing R Extensions" for more information.