Best way to improve PR ?

yes, this is the right idea to build page rank..You can also do guest posting in top page rank sites

get some actual high pr backlinks (like homepage backlinks, actual high pr blog comments) to increase page rank.

Matt Cutts announced that the pagerank isn't going to be updated for the remainder of 2013.
Why waste your time on this metric???

Watch the video below, Hope this helps.
[video=youtube_share;M7glS_ehpGY]http://youtu.be/M7glS_ehpGY[/video]