There are really a lot of already pre-build Dashboards for each service to get a feeling about the service. I tried to create my own with some meaningful metrics, this already took some time, since there are really a lot of metrics built-in. I came up with a dashboard that had the request latency split up to the different services and one overall. The source code can be accessed here.
Based on those dashboards, some meaningful alerts can be implemented.
The dashboard can be accessed here