So far my most successful method has been to do directory submissions. I found a service via google called gotosubmit and they do the submissions for me. It is not that expensive and it works way better than forum linking in my experience.
I am interested to hear your opinions. I have read through the entire 60 day backlinking experiment but just did not find that forum links work for me.
I have also used 1 way links with success too. I stopped using them though in favour of directory submissions.