Once your buckets are laid out, start doing some research on keywords you're interested in rating for. So you don't have to spend money on keyword tools just yet, jump to a Google search page and start typing in the words you're looking to focus on.
Pro Tip: Avoid using too many keywords on a single page. Strategically create pages that use important keywords in the page header and the rest of the words in the main content, but really try to focus on either only one keyword or a few specific words/phrases.
From the google search results you'll begin to see what people are searching for when typing in your keywords. You can easily incorporate those other keywords into your buckets too! Check it out: