To get a good rank on google for your website you have to do on page optimization and off page optimization on your website. Also add new content time to time on your website. It helps lot for ranking. But content must be fresh and not copied from other sites. There sre many companies which provied SEO services. You contact to one good company. They do SEO on your website to rank your website.
There are so many ways to build your site's Google rankings. You can use on-site optimization techniques or off-site optimization techniques. On-site techniques are the ones that are initiated on your siet such as creating content that is keyword rich. Off-site techniques are done on other web pages like building links on other sites.
Yep unique content is important, add content as often as possible. Also you can create related pages to your website on facebook and other social media(and post there news and links to your website(that is for if you need more visitors).But if you need high ranking -- SEO
If you add your site to 5 PR-5 websites that relate in your topic and add new contents regularly. You will get top PR in every year. Do not throw your site to any seo companies because they are all using black hats to keep future down.