the more information that you give to google about your business the more it can identify you as relevant to users that are searching for your services and or products. Google may be aware that you are a restaurant but does google know that you cater to families or vegans? Does it know your price range, whether you offer parking? Filling in as much relevant information as possible means that you will appear more often in searches and google will be able to associate you with various searches that your potential customers are likely to be looking for. This information should be accessible to google and regularly updated e.g. if you offer services make sure you update these regularly and that all services are included.
Google responds to activity on your google my business page and it knows that users interact more with pictures and posts within the knowledge panel. Regularly posting with news of what you are doing, menu changes, achievements, activity etc, is highly beneficial to optimizing your google my business page. As far as photos go, google will recommend what similar businesses are doing and how many photos you should have. This varies based on how relevant photos are to your business but it is safe to say that if you have a reasonable amount of images and update them from time to time there will be an increase in visibility through your google my business page.
This is arguably the most beneficial thing you can do and yet the majority of businesses struggle to maximise the positive impact reviews can have. It can be incredibly advantageous to encourage your customers to leave reviews. There are many ways to go about this, you could simply suggest that you would appreciate it or perhaps even offer discounts in exchange for reviews. Whatever way you choose to encourage your customers its always worth asking. Many of your customers would be more than happy to leave a review but they may just not think to do so if you don’t ask them.