The onpage-offpage model a user above has cited essentially sums not only the basics, but some meat and potatoes when it comes to proper, "best practice" SEO.
It has long been proven now that gaining social media presence in the form of likes, pins, tweets, shares (and the multitude of other gimmicks with deviating social networks) is perhaps one of the best ways aside from organic
link building to raise a webpage's page rank with virtually no work from the webmaster as it integrates with promotional phases. You may have to point out to your viewers that you would appreciate a like or a share (there is nothing wrong with this, and it can help you get a higher result than you ever would have gotten otherwise) if they find the content on your site useful, to get them to build your presence for you. However, it is definitely worth it in the end.
Good backlinks will likely forever remain the forefront of harvesting a good page rank with SEO. There are plenty of ways you can go about doing this. Essentially, wherever you can type or post HTML, you can acquire a useful backlink in some form. Make sure that most of your efforts are accompanied by quality contributions, and you will never have to worry about guilt or having your link being deleted because someone was offended.