Off page optimization

what is offpage optimization ?off page optimization relates to getting quality backlinks in more and more quantity.there are various things which should be kept in mind while link exchange.These are as follows :what is your site related to?
Which websites link to your website ?websites linking to your website should be relevant this is the main thing which google notices,if there are enormous amount of links pointing towards your site and all are irrelevant then all the thing goes in vain as google points these link to either purchased or link farms
The number of websites linking to your website
The Google page rank of the website linking to your website Main thing whihc all webmaster consider is the google page rank of website linking to them.The more page rank of website the more your website will get importance.
The page title of the website linking to your website as it shows relevancy to your website
The anchor text used in the link linking to your website anchor text holds a great importance with which your link is placed at link partners website.Dont use same anchor text with all link partners as now there is possibility that google can find out that these link exchange are not natural.
The number and type of links linking to the website that's linking to your website. IF more websites are linking to your link partners website it is obviously that your link partner's website will get importance and so as your website
The number of outbound links on the website that is linking to your website
The total number of links on the website that is linking to your website The less links located on the page, the more a link from them would increase your ranking.
Whether or not the websites linking to you are deemed by Google as an authority website means whether the site which is linking to you is indexed by google or not.