Title should have keyword, description should have keyword and your link back to your page should have keyword. but its all difficult because on DP you have to post meaningful posts
use your keyword on your post title and once every 100 words or so in your article. if you have any option to use subtitle in the article, then use your keyword on the subtitle as well. tag the post under the proper keyword as well
It all comes down to relevancy according to Google. The more relevant your website or a single post is to the search the better Google presents you in the serp. The key points to remember are (as mentioned above): first word of the title should be your main keyword; each paragraph should have your main KW in bold, sub headers should include your KW and the last sentence word should include your KW.
Basically its all depend like using your main and targeted keywords in the title tags as well as at least two times as anchor text within the body paragraph of the main post, then use bookmarking to get required and desired results from particular keyword post.....
Bold your keyword one or two times.It should be present in your page title,meta description and page body. It should be spread throughout the page. Overall keyword density 2% Thanks