My site is on 50-60th pleace in google serps for all keywords for over 1 year. Before was in top 10 then lost its position and move to 50th place, i wait couple of months and then my site was back in top 10 then i sterted to build some backlinks and this was my biggest mistake. My site got -50 penalty again till today (over a year). I'm still building backlinks, site is PR=4 now but still on 50-60th place for all keywords. How to recover my serp positions?