Find out what keywords your competitor uses and how often and compare it with your own page. Ideally, choose a competitor ranking above you, and find out which keywords to use more, and which might be overused.
Have you noticed that sometimes when you search on google, some results don't even directly mention your keyword?
Google has got much better at
Don't keyword stuff! Use keywords naturally, use synonyms and various variants of keywords (LSI keywords). Using them will allow search engines to get a better understanding of the topic of your content.