Use the keyword once in the title , once in the meta tag keyword area, once in the meta tag description area, once in an ALT description, once in a heading also create a link on the page with the keyword in it. Title Keyword Density A keyword percentage factor is applied to the title as well. Titles are arguably the single most important keyword weighted factor on a page. The title is arguably the single most important area for effective keyword placement on a page so target the title well. Finding the right keywords and using them in a compact manner will return better results than using a plethora of words in the title.
Some search engines penalize for using the same word excessively.