Raise your Page Rank

I've actually given up on this website ranking thingy. It can get frustrating. I really do not understand how this thing works. You were once a 5 then all of a sudden you were slapped a zero. Frustrating right? Much as I want to raise my page rank again, I just don't have the correct resources to do so. I heard that paid web directories can really help you get back to where you once before, a higher than zero page rank that is. I will have to look into this since I really want my PR back so bad.