I prefer URL,Title Tag,Meta Keyword, Meta Description, Body text,H1 tag, Anchor text this all are most important area to include keywords.
Keyword popularity is a moving target for many keywords. As they say, one day you are hot, the next day you are not! Some keywords are long lasting, and others are only short lived. Considering keyword trends should be part of your keyword strategy for creating predictable SEO results.
Research keywords and keyphrases (multi-word phrases) before you create your web site. It’s important to create your web site with keywords and keyphrases in mind and to put them in place as you develop the pages and content. Target keyphrases rather than single keywords. Single keywords are much more commonly entered by web users, which makes them more difficult to target effectively than multi-word keyphrases. Unless the single keywords are highly unique, your best results will be achieved using keyphrases. Use longer words and plurals. If you target plural versions of your keywords or phrases, you’ll get hits from people searching for the singular and plural versions of those words. Focus on a few specific keyphrases for each web page. Pages that rank well in search engines tend to focus on specific keyphrases that usually appear in the HTML title element, heading elements, breadcrumb navigation links, product names and descriptions, and crosslinks. Create keyphrase-rich text content, especially for your homepage. Identify the top two or three keyword phrases that potential visitors would use to find your web site, then write 200–250 words of homepage text that utilizes those keyword phrases—not the other way around. Follow this approach as you create content for other web pages, too. As noted above, keep in mind that titles and headings are considered more important than other content by some search engines, so consider this as you optimize your content. We’ll discuss the topic of optimizing your markup for search engines in just a moment. Include keyword and keyphrase research in your ongoing web site SEO maintenance plan.
You could benefit best if you use your keyword wisely by putting it in your title tag, meta description, somewhere in the first 300 words of your website, use it in your title headings which are using either H1 or H2 tag, and in the alt attribute and title attribute if you will be putting images.