By default, should local packages are expected to be in ~/texmf not ~/share/texmf (they are expected to be in ~/Library/texmf on a Mac). So try putting your new version of the package in ~/texmf/tex. This directory should be found first when latex searches for packages.
Furthermore, the local texmf needs to follow the TeX Directory Structure: (you don't need to create all of these directories initially, but you do need to put things in the right places when you add new stuff.)
• bibtex directory This is where bib files and bst files go
⁃ bst directory Put bst files here
⁃ bib directory Put bib files here
• tex directory This is where new packages go
⁃ latex directory Put latex packages here
⁃ plain directory Put plain tex files here
⁃ xelatex directory Put xelatex specific packages here
⁃ xetex directory Put plain xetex files here
⁃ context directory Put context files here
⁃ generic directory Put files that are usable with any TeX flavour here
• doc directory
⁃ put documentation files from packages installed in the tex directory here.
Putting the documentation files here allows them to be found by the texdoc
For example, suppose you have the new package
cool-new-package. If it's a latex package, the package will come with (at least) a
.sty file, and some documentation files (often a
.pdf version). You would create a directory in
cool-new-package and then put
cool-new-package.sty there. You would also create a
cool-new-package directory in
~/texmf/doc and put the documentation files there.