Looking for new ad group themes? If so, check out Wonder wheel that visually presents connections between related searches and search term. This tool can be a powerful resource for creating new ad groups. To access, do a regular Google search, click "Show options" at the top of search results page. Then click "Wonder wheel" under the navigation bar on left side.
Although Wonder wheel suggestions are a great guide, if a logical ad group theme is missing from suggestions, add it. If the tool suggests ir-relevant themes don't add them. Once you've list of new ad group themes you can use keyword tool to identify keywords for each ad group. Input each ad group theme into tool, select "Search" and then sort by "Global Monthly Searches" to refine the list to those with most search traffic.