Remember, all the best practices of typical web architecture still apply. For an excellent overview on the subject, please refer to Michael Nygard's excellent book Release It! Design and Deploy Production-Ready Software. Writing your app in Meteor doesn't absolve you of auditing third party libraries, writing circuit breakers, wrapping calls in timeouts, monitoring your resource pools, and all the rest. If you want your application to perform well, you need to make sure you're using stability patterns, and avoiding anti-patterns.
Stability Patterns
Integration Points
Resource Pool Contention
If these concepts are unfamiliar and don't seem like second-nature to you, it means that you haven't brought bigger production systems online. Buy a copy of the book. It will be time and money well spent.