We aren't marketing experts.
Clients ask for our advice on Adwords and Analytics often, usually with a statement along the lines of "I'm sure you've picked up something from your other clients..."
While that statement usually isn't wrong, it doesn't mean that what one client is doing is the best thing for another client to do. There is no one size fits all strategy when it comes to marketing and analytics.
Clients expect us to be technical experts, and for many we're the only resource they have to reach out to for guidance. Because we're in a position of trust, it's important that we avoid giving clients any specific advice on marketing because they will take it to heart. We also need to be clear that our refusal to give them advice is to protect them from making a potentially costly mistake.
So what can we do to help them?
We give them the resources they need to help themselves.
Here is Google's Ad Academy: https://landing.google.com/academyforads/
Here is Google's Analytics Academy: https://analytics.google.com/analytics/academy/
If they want to improve their marketing they're going to need to put in the work and those links are where they can start.