You can use lots of methods but all of them will involve lot of time. Comments on blogs and forums, social bookmarking, summiting to directories. Those are all good for your seo pursose
You can increase Page rank by Quality back link. you can do link exchange with same theme and good pr sites, Press release, Article posting into good article sites etc.
If you want to increase your website google pagerank through backlinks all you need to do is just approach paid link company which is present in the market for many years. Many afraid with paid links and they say google will bring their website down if the number of links increases drastically but i dont think soo. I know many companies who are top in keyword searches. They reached only through increasing the backlinks to 5000 and above and they keep on do that through paid link building
page rank will come from quality original content. for backlink you can register popular sites like digital point,and social webs like facebook and twitter etc and other websites signup and in about me space tell about yours and with your website link it will give good back link
Do good quality backliks related to your niche if possiable. Forum comments and blot comments work really well for me personally. I also plan on doing artices. Facebook fan page keep in mind thats do follow but lots of traffic. social bookmarking, directary submission. Backlinking off page seo is a ongoing process it never stopps. Just stick with it no matter what you will have low poits and high points.
How great your open discussion regarding signature, some forums do close signature due to such kind of messages.
as well need to submit your URL in google search engine google related all networks for backlinks. there are a lot of other techniques used for backling. submit site to directories article submissions classified ads and google indexed sites that is very beneficial. Try to post your site better than your PR