I think I found this somewhere in a Guru template collection, but here is the content from a card we use to TRY to create some best practices:

Guru allows your team to quickly leverage the content they need, when they need it, without leaving their daily workflow. The following article provides guidance on creating content in a way that sets you and your team up for success.
 

Seven Key Tips When Creating Content

1. The first content you add to Guru should be high-value knowledge that your team accesses frequently. When a user sees meaningful, up-to-date content in Guru when they first access it, it shows them that Guru is their single source of truth and can help them respond to customers more quickly. It's also important to have enough content for the team to evaluate Guru's impact. We recommend a minimum of two use cases. Examples of a use case to include:
   1. Product FAQs
   2. Sales assets
   3. Competitor information
   4. Trouble shooting guides
   5. Key process-oriented information
2. The primary use cases should be added prior to rolling out to the team, so users don't enter an empty account. In addition to yourself, we recommend inviting your subject matter experts to assist with your content curation.
3. Content should be easily searchable and discoverable by your team. The title of a Card should reflect the way a user would typically search for the information it holds. To further improve search results, the Card should incorporate Tags that reflect its topic. Here are some guidelines you might use:
   1. Keep it short! No more than 10 words total, and short enough to keep the card's URL as concise as possible.
   2. Keep it searchable! Include key words your agents will search for, and make sure the title works effectively with your established tag structure.
   3. Keep it unique! Make sure your card's title distinguishes it from other cards on a similar subject.
4. Avoid duplication of information so you're not having to manage more than one Card covering the same content. NOTE: The same Card can be viewed on multiple Boards (as long as the Boards are in the same Collection--read more here) and Cards can be linked to other Cards).
5. Ask the team to utilize Guru Q&A when looking to add information. This ensures that the answer they need is automatically shared with the team and helps Guru learn how your team searches for content.
6. Cards should be easily consumable for the user to digest and then relay to customers or other teammates. Unlike docs stored in a shared drive or other repository, Guru's Card design is ideal for surfacing the most relevant content in just a moment. Cards are more likely to be read and consumed if they are less than 1,000 words in length (which equates to a one-page doc).
7. It's helpful to think about breaking down content by subtopic. If the general topic is Product FAQs, each question and its answer could be its own Card. This allows your team to search and find just the bit of information they're looking for, rather than scrolling within a longer doc.