write quality content and the backlinks will be natural, thats called "natural seo", you will get links from social media sites, trackbacks, ect. Make contests, give away something useful to your users like ebooks, trials, ect.
Those link building methods are of less valuable nowadays. Most of them are considered spam. Let me remind you that Google is not counting low quality links. That means you will not be penalized in building those kinds of links. Get to know people! Build relationships with them, because it'll come back to you in the form of links.
Do guest posting on the blogs related to your niche. Also try article submissions, daily blog posting, web 2.0 links (Squiddo, Hub Pages), blog commenting, etc.
Now forget old methods of link building. Google clearly says that just create content and don't worry about ranking, ranking would be decided by Google, so you have option to do on-page SEO and create useful content. However, you can build some quality and relevant links but make sure your site has content as well as visitors too, if you are building links only and your site doesn't have good content then you won't get much benefit, instead you would be penalized as well. Apart from all these, I would say that guest blogging is performing good these days, try using this with relevant sites, it would help of course!
According to me , following techniques does help you to bring ranking. Article submission with natural contents Social Bookmarking in high pr sites Blog commenting theme based Guest Posting
Find blogs and forums within your site's niche and then participate in those by commenting on posts or doing guest post. This may be true, but you have to do your best to promote your content. Everybody else is creating content and posting them on the net, you have to make sure that your content gets noticed. Promote your site on social media sites like Facebook and Twitter to get both backlinks and traffic. Have a good weekend!
Focus on quality links rather than quantity to avoid penalties from G see http://www.searchenginejournal.com/the-definitive-guide-to-penguin-friendly-seo/57196/
Also, make sure if you are buying backlinks to make them diverse. Say your website is example.com, have a wide range of anchor text link back. Some keywords, some branded/urls (Example, Example.com, etc.) and some random (click here, visit site, etc.).
In regards to your opening question, this subject matter has been considered many times. What I found very helpful is a thread on this forum that provides a useful visual strategy that will help you with some different ideas and suggestions to link development. https://forums.digitalpoint.com/threads/my-2013-linking-strategy.2631274/ Ultimat1 goes in detail via a useful image with regards to a link strategy that incorporates pretty much everything from social media to blogs and Yahoo answers. It's a strategy that makes sense but obviously it takes a lot of work and patience. It takes time to develop those different steps. I personally have boomarked that thread and I go back every so often just so I get a brief refresher of ideas. In addition here is a brief video of Matt Cutts of GoogleWebmasterHelp talking about different effective techniques for building links: youtube.com/watch?v=MkLFlaWxgJA Hopefully this info will provide some assistance to your opening question.