I think you should get your all questions answers here: http://www.squidoo.com/how-to-build-link-wheel
A natural looking backlink profile is absolutely the way to go. This means including a wide variety of links in your profile, such as blog posts links, comment links, forum links, social media links, article links, one-way links, reciprocal links, and even links varying in quality. It also means not focusing too much on one anchor text either. Make sure to vary the anchor text up with different keywords as well as some more natural anchor texts, like your blog's name. (Remember, sites don't usually get linked to on very specific, deep-page anchor text. It's usually the sites name, or something more generic. Keep that in mine as you're selecting your anchor texts).
there are many way to link building like one way link building,two way link building,three way link building. search engine to weight on two way link building. i think one way link building is good for our site. like social book marking, article submission,forum posting with signature of our site and do follow blog commenting .
I do not think that link exchange and link wheel are important things because many of the people don't do it correctly ...
Link building is the way to get Ranking your site...Higher and higher, it is important to know that they need to be the right kind of links... Here are just a few of the benefits of link building: • Links are viewed as a ‘vote’ for your site • Inbound links offer a route to your site from other sites • Links to and from relevant sites help search engines assess what your website’s overall theme is • A higher link profile can boost your site’s credibility and trust • More links means more avenues for website traffic to find you • Improved rankings for your targeted keywords • Improved search engine robot crawl rate
Blog comments does not work nowadays. Go for Guest Posting or article exchange to get some good quality one way link . It's time consuming I know but it's worth deserving.
Use every technique to build links to your site. It is right that one 0pr links doesn't work but something is better than nothing. Don't depend on one link building method use every method one by one but I want to say that content links are more reliable. So in this way article submission would be great it doesn't mean other methods are not good. Links from web 2 properties like blogs, forums would be also good technique.