As many high PR links as you can get, will give u a good Page Rank. If your website is not a web directory then you do not need PageRank, just focus on getting traffic.
Get quality backlinks from relevant niche websites having good PR and unique content updated on daily basis.
You all have suggested a very good option but forum posting and blog commenting can give you best result.......... and can also go for SBM..............
you need to do onsite review on your site as well. maybe there is a hindrance in which the link juices can't be pass on your site. Well, if the condition of your site is okay then I think you need to do other off page optimization for your website.
Try to get high PR backlinks for your home page and try to get single outbound link from a high pr page. Do social bookmarking , press release, blog posting and forum posting.
Rakib Bhai,You should get back link on high PR related to forum,blog.I do believe it will help you a lot.
1st Never give lots of out going links from your site, next find some good high pr sites that are related to your niche(dofollow sites if you can find is better). Do guest posting as well. Your pagerank will be good.
All about PR is depending only on the back links. Try to get back links of high PR with relevant niche, quality links, from Less OBL sites (provides more link juice). Getting links from authority domains may increase your PR faster. And somebody says, user engagement and traffic in the site also helps in increasing the PR of that site. My friend also maintaining one blog and he has only 45 back links those too from low quality sites but he keeps that site with PR 3. This is only because of many users engaged in that blog it seems. I also think so that traffic and user engagement also increases the PR.
Can you share which site's PR you want to increase? I am sure that if you build some relevant links on relevant site then you will get enough backlinks.