Thats an easy one!

Get backlinks from high page rank websites.

A PR of N/A tells me Google has yet to make an evaluation yet. If they did, it would be) or greater...just build some links.

Only backlinks pass PR, so the only way you can increase your PR is to get backlinks.

... and then wait a long time to verify it's gone up, since Google updates the public-facing PR values very infrequently.

Don't concern yourself with what your PR is - just work on ranking your sites. Good rankings bring traffic, which can be turned into money. PageRank alone doesn't generate traffic, and doesn't earn you money (unless you're selling links from those pages with a high PageRank).

(By the way, there's no such thing as a PR-x site - only a PR-x page: sites don't have PageRank; pages do.)

Try to gain some quality backlinks from high pr sites , also have some socialbookmarking on high sites and directory submissions .

Cheers

Ignore PR! (well not completely)

I use the seoMOZ software to judge page authority. I am sure there is some free software available as well. Just work on creating quality content and gaining links to your site.