Search your competitions backlink report and figure out what their best DO FOLLOW backlinks are. Then, go to those websites and figure out exactly how they got the backlink. A lot of times, it's just a simple forum signature - some high quality forums still offer DO FOLLOW signature links. The main this is DO NOT SPAM! Create a nice profile, add your signature link CONTEXTUALLY! Then, comment on a few threads and wait for the Google bot to come along.