Step 1: Scope the problem

You can't design a system if you don't know what you're designing.

First, ask questions to clarify what you need to implement. Then make a list of all major features and use cases that your design must cover.

For example, if you're designing TinyURL, that list might be:

• Shortening a URL to a TinyURL
• Analytics for a URL
• Retrieving original URL from a TinyURL