Now that you've chosen the keywords for your site here are a few tips on how you can optimize your site using those keywords.
1. In your page title, include only your main keywords. Shorten the description of your site, enumerating only the main keywords. If possible, combine keywords with the same words on them. You may also use the symbol "|", or any other symbol, to replace conjunctions like "and" and "or".
2. Place your most important keywords in the h1 tag. And it should be located at the topmost portion of your website.
3. Place your secondary keywords in the h2 tag.
4. On the body of your text, try to include your keywords in every paragraph. Avoid overdoing it as google will treat your site as spam and it won't rank well. Like for this page I am trying to optimize the words "Online Marketing" and "SEO Blogging".
5. When writing, try to mention each keyword in a natural way. It would also help to change the style of the font (bold, italicize, underline) for your keywords. However, do this only once per page.
6. Add a picture to your site / page if possible. Name the picture after your keywords.
SEO Blog: Optimizing your Site