One of the initial challenges in building a smart home skill is account linking. I found two Amazon Developer articles written back in August 2016: "5 Steps before developing a smart home skill and another written back in April '16 "creating your first smart home skill"
There are other articles giving bits and pieces of development code examples such as Coding Smart home skills adapter directives using node.js and that discusses payload version 2. Additional bits and pieces covering converting payload version 2 to 3 and JSON formats for headers, etc., can be found but nothing that brings them together into a coherent example.
The developer console and lambda development dialogs have changed since these articles were written making them error prone when following the tutorials. Are there newer examples of writing a smart home skill that I haven't found? Are there any current node.js scripts for use as a template for a smart home skill?
Also, given that a developer must switch between two web pages (lambda function and Skill) to cross pollinate the other's information - which involves multi-step cutting pasting into a text file then more cutting pasting into the web page in the appropriate fields - it seems very clear that a single developer web page to integrate the two (lambda function and Alexa Skill - plus don't forget the security profile info) would make the process a lot less error prone and so much faster.
When I finally got my "test app" to account link successfully, I had gone through the process several times - creating from scratch new test lambda functions and new test skills - with a variety of errors for several hours. In the end, I don't know what made it work successfully. I was surprised when it did. Some updated tutorials and templates for the current Smart Home Skill API would be welcomed.