My App's data usage is too high, how can I solve this?

I have a Meteor Cordova mobile app. When I tested it, I noticed that the app used 100mb of data in just 10 minutes of using it. I’m wondering if I can somehow test how much data does my app use, and how can i lower the data usage?

Meteor version 1.8.2
App uses pub/sub system

The Galaxy guide has some great tips here:

In addition to the suggestion above, you want to inspect the size of your DDP packets using Chrome Dev Tools for example. And then make sure to use field projections/pagination to eliminate any non required fields/data.