There are various tools which you can use to find the keywords. Once you will find the target keyword then you can start building the contents which will have that targeted keywords.
You should find the list of targeted keywords. Also, you should study the keyword phrases which are related to your keywords as well as you should perform the competitive analysis about what your competitor's keyword phrases. You can find the opportunities that is keywords which can attract the more traffic to your site.
You should add the keywords in title tag, meta tag.