How to build the interaction of an Android application with the server side?

Question

Mobile development

There is an application that is planned to be rolled up by exchange with a web service. Self-written service - REST with all the goodies.
Interested in the approach. Technical means and tools are now clear how to work with them - this is another question. I'm wondering where to start, what to pay attention to? Surely there is a certain standard scenario that explains at least the basic steps, what to do and in what sequence, what bottlenecks.
I would be grateful for tips.