Here is some simple tips:
1) Optimize your web pages for content

This is very important, most people think that link building is more important than the content itself. But you can’t undermine the importance of Web pages themselves. Optimize your web pages for the most relevant keywords.

If you have keywords that can have different category then better add separate page for them

2) Optimize pages for title and meta tags
In addition to content each page has to be optimized for title and mettags.
It is pitty that most people only focus on home page and ignore rest of pages.

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3) Social Media Optimization
SMO is another way for increasing the traffic directly.

4) Relevant, interesting and useful content

Let your web pages have unique and interesting content which are useful for visitors and who can keep coming back to your website. Always keep updating your content if you can.

5) Blog
Blogs are dynamic and easy to promote. They can be used to bring traffic to your main website.

6) Articles
Write articles and provide links to your main website.