I need some expert advise
 

Hi
I'm doing off-page optimization for an It company website for four months now, but the PR of the website has not increased. Please provide your input.

do all off page activities and backlinks from high pr websites...

Make sure you did the On Page Optimization for the site... Then Go with the Off page Optimization...

I think Link Exchange and Forum Posting are the very good tactics for building link...
I prefer blog Posting, forums & Bookmarking these are the best strategies

Well, if you want to increase Page Rank of the website then increase your quality backlinks because PR is depend on backlinks according to Google.

PR only take count on do follow link. To increase it, must get high PR do follow link. If everything doing correctly and still no update, then wait time pass. PR cycle update is about 3-4 months.

I agree with Johns�you have to do some link building work with high pr websites and also try to increase traffic over the website through classified ads, social media optimization. Once the website traffic would be increased the definitely your website page rank also increases.

You must have to create back links on quality sites which has already a huge value of PR such digg, stumbleupon, reddit, slashdot, and create links in high PR forums.

Do

Forums
Article
Pressrelease with high pr and mostly do ,do link building that help you to increase page rank your site