Try using different title (minor variation) in each directory
Hyperlink any 2 of the 5 keywords you highlighted. Vary these keywords/anchor texts randomly in different article directories. Suppose, there are 5 keywords; a, b, c, d, and f. In first directory, hyperlink a and f, in second directory, e and b, and carry on. It’ll help getting you backlinks at different keywords using same article.
If some website allows, give backlink from your resource box.
You get all articles approved that were syndicated to top 10 directories.
Bookmark 10 different URLs randomly to most popular social bookmarking sites.
Digg the url of EzineArticles.com, Stumble the url from Goarticles.com, Reddit the url from ArticleCube.com and carry on. It’ll give you best, safe as well as natural backlinking. Don’t bookmark more than 2 different articles a day if you’re running article marketing campaign for many websites. Many social bookmarking sites may ban you considering spam submissions.
Recommended Do-Follow Social Bookmarking Websites