Don’t put packages not coming with the main distribution there. Rather use /usr/local/texlive/texmf-local; otherwise the added file will vanish when an update to the main distribution will be done.
From the Terminal, assuming you are in the directory where the package files are:
% sudo mkdir -p /usr/local/texlive/texmf-local/tex/latex/cleveref
% sudo mv cleveref.sty /usr/local/texlive/texmf-local/tex/latex/cleveref
% …do […]