Keywords may be the single most important factor on your website. While they cannot be removed from the other important factors, such as quality authentic content and a great on-site experience, it is great to know how to use them.
As mentioned in our other keyword post, keywords are the words on your page that are scanned by search engines to help them determine what the pages on your site are about. There are various kinds of keywords, from short-tail 1 word keywords to more detailed long-tail descriptive phrases. You can do keyword research to try to find more specific keywords to write about as topics.
Use keywords in your url, H1 and H2 tags, page titles. Use the keyword also within the first 100 words of your body copy. The focus keyword of each page should generally be the topic of each page. For each of your keywords, you can have a different page. This is a great way to add additional and new content to your website, and helps you rank higher in the search results.
You can certainly use more than one keyword on a page, however the focus keyword should be the general topic of your page, and any other keywords on the page should be supporting ideas.