What do you suggest to do for acquiring quality backlinks to improve search engine rankings and credibility among all major search engines
Everyone knows naturally given links not made by you are best and not made by others you know or that other known patterns exist for are the best backlnks, that is those that are freely given. SERPS are about providing the end users with the best most relevant search results for their queries, at least it better be or you can kiss your SE goodbye the further it deviates from that objective, as everyone will get fed up soon enough, but linking is only one small part of that so not that much of a biggy you can't get page 1 SERPS without it.
If you'd like to improve credibility - then go for social media marketing, in particular get social signals on G+ and Facebook. As for improving search engine rankings, there is no one single way to get quality backlinks. To start with, you can run a backlink checker and find out which links work for your competition and then come up with your own strategy.
It is best topic for recover the site ranking after Penguin update. Now this time Google algorithm has been changed. Google fewer to weight-age sites in search engine. For good ranking in search engine only do quality works. Content based informative link is good to promote. Use of hyperlink in targeted keywords is not good, use only alternative keywords.
Guest posting and directory submission are the best ways for acquiring quality back links to improve ranking in search engines.
Thanks all for your valuable feedback. Thus far Guest post is on top. Is that mean that we shouldn't use anything else apart from Guest Post?
You can use almost all the methods of link building, this way your link profile would look more natural to Google. Any site you are using, please make sure they are relevant and quality site for better result.
Nowadays Guest posting is very popular and lot's of users work on it and improved site status and profile related website details add it is best option for back links.