Hi,
I am jack, working as a designer.I know designing.But i am not much aware of Search engine optimization.What is the best way to promote a website?

The best way is to know your target market carefully. The know what are the possible keywords that are going to type when they are searching for info. Then target and optimize those keywords in SE. The best way to find high traffic keyword is through google adwords or keyword discovery.

This will help you in optimizing your site:
* blog commenting
* blogging
* social bookmarking
* Social networking
* article marketing
* submit your website to site directories