When it comes to User Interface (UI) design, your job — whether you're a designer, developer, UXer or a mix of all those things — is to make sure that no aspect of someone’s onscreen interaction happens without explicit intent. The UI design choices we make have to reflect the user’s motivations, expectations, environment and possible actions.

All of those things manifest themselves in the User Interface — so what people see on the screen is usually the sum of their understanding about what this is and how it works.

So what we show them has to do a hell of a job communicating what’s there for them, how it’s organized, how they get to it and what they can do with it once they do.

The principles, practices and real-world techniques I'm going to show you here are the same ones that have informed graphic design for hundreds of years. And while that may sound like blasphemy to some of you, I guarantee you'll see why and how they apply equally to the world of digital design — especially for mobile devices and their small screens.

I'm going to give you 50 lessons packed with timeless, ironclad, unchanging rules for good UI design that you can apply to anything and everything you ever work on. Trends will come and go, and it won't matter: your UI will still be useful, usable, appropriate and relevant for its users.

You'll learn how to make it easier for people to interact with what they see on the screen – whether they know what to tap, swipe or click, and whether what happens meets their expectations and moves them closer to their goals. You'll learn how to create and apply hierarchy, color, contrast, typography and gestalt principles to design appropriate visual cues so people know where and how to take action.