Write more unique contents with useful information and promote it on high pr forums or blogs to get good backlinks. It'a easy & best ways to get high pr in short time for a new site
You should try to get back links from high page rank authoritative websites. You can add fresh and keyword reach content with your targeted anchor text. For increasing page rank take an advantage of Link Juice.
If your website new then just putting Article, blogs and forum section in your website as sub domain and starts content publishing and wait next Google Page Rank Updates, I am sure; Page Rank of your website is going Increase Permanently.
There are no short cuts or easy way to increase fast PR. Google update PR in cycle of three months and they will not give you direct 4 or 5 PR. So it will take at least one year to get PR 4. You should start to gathering back links with high page rank web directories for increasing PR of web page.
Write more unique contents with useful information and promote it on high pr forums or blogs to get good backlinks. It'a easy & best ways to get high pr in short time for a new site..