Quick tip for improving your search engine results: Create "buckets" (or columns) of general business-relevant ideas where you can dump the different keywords you'll think of later. These buckets/columns are the broad categories your business focuses on (for me they would be "Website Design" and "SEO").
Once you have your broad categories on which to focus, think of search terms people would type into search engines like Google or Bing in order to find services like yours. Drop these into your buckets to begin the process of indentifying keywords you can include in your content.
You'll then take these words or phrases and begin to research them to determine which have the most relevency and best chance of getting you found online (more on that later).