try to get links from higher pr site all links are do follow. link wheel is very important to improve pr.
Simply PR is depending on your site back links, more techniques for getting back links, you can make quality back links.
First of all the content of your website should be unique and good, than you should try to create more backlinks for your website.
Always concentrate on your content.Hit the directories because they are usually well spidered and are a great way to help get your site in the engines quickly.
Best way is getting links from authority sites in your niche, ofcourse getting them to link to you is the hardest part, if they have a blog you could try adding useful comments to the blog and if it gets accepted, over time will pass some PR juice