NodeJS is a popular Javascript runtime environment to write quality apps. To build the quality apps you need to write quality code and follow some best practices during the development.

Organizing the code: When you start writing the codes for your application you will think that you are able to understand it but after a month or a year even you will face some confusion while you read it. To easily read a code it needs to be simple and organized. To make it look organized the code can be grouped into small chunks. 

Avoid blocking the execution - The modules that are in different files can be included by using its built-in require function. You should use the require function at the top of the file to avoid blocking the execution since require is asynchronous.

Style guide- There are style guides which you can checkout. It will make you more productive as it narrows down unessential choices. Set a specific developing style and stick to it. 

Asynchronous code- To avoid blocking threads async code is the good way. Synchronous functions in JavaScript block other code from running until they are complete. 

Code linter- Code linter helps to check for basic quality issues in our code. 

Vulnerable dependencies- tools like npm audit or sync.io can be used to check for vulnerable packages. This helps to avoid vulnerable dependencies in your code.

Testing- test every functionality after finishing the coding for that functionality.