#1. submit an article to article directory, put a link #2. leave your coments on dofollow blog #3. link excange #4. buy link (not required)
you should do quality and PR link exchange with start social book marking, article and blog comment posting..
You can't "build" quality links - not at least on consistent basis. Quality links are usually EARNED - by creation of genuinely useful, quality,linkworthy content. So identify the needs of your target demographic and produce lot of TRULY HELPFUL content - then let other authority sites in niche know about it - they will not be receptive to citing your resource unless it's of high quality and useful to their site visitors. I am afraid there's no magic bullet really ninja_va