QUOTE: “Consider where user-generated content might appear on your site or app, and what risks to your site or app’s reputation might occur from malicious user-generated content. Ensure that you mitigate those risks before enabling user-generated content to appear.Set aside some time to regularly review your top pages with user-generated content. Make sure that what you see complies with all our programme policies.” Google Adsense Policies, 2018
If you're struggling to think of more keywords people might be searching about a specific topic, go to Google.com and take a look at the related search terms that appear when you plug in a keyword. When you type in your phrase and scroll to the bottom of Google's results, you'll notice some suggestions for searches related to your original input. These keywords can spark ideas for other keywords you may want to take into consideration.
The SEO starter guide describes much of what your SEO will do for you. Although you don't need to know this guide well yourself if you're hiring a professional to do the work for you, it is useful to be familiar with these techniques, so that you can be aware if an SEO wants to use a technique that is not recommended or, worse, strongly discouraged.