Packages are not my area of expertise.
At first your package is  ".m" file  or more ".m" files. (may include additional data or documentation)

See link:
http://stackoverflow.com/questions/4641512/how-to-install-new-packages-for-mathematica

There is written:
Packages are placed on $UserBaseDirectory/Applications or $BaseDirectory/Applications.
If you want more comfort and your own documentations and more features, so you need install Wolfram Workbench.
My answer is blunt, because I do not know all the details and describe them takes many times.

I posted the attached notebook to an earlier question that asked for similar advice.  I wrote it for a consulting client of mine.  It is not the whole story, but it provides some hopefully useful pointers.

--David
http://scientificarts.com