I think these are pretty good way to meet partners.
I have never tried tennis pick up lines (I don't like to use one anyways..^^; ). I shall give it a try sometime.
I met my regular tennis partner 2 yrs ago on tennis league team. Another one on tennis team that I took.
I think it's also a good idea to take a lesson from a pro, ask him/her if s/he knows any player in the same level as you are.