Skip to main contentSkip to navigationSkip to footer
Principles
Parts
About
Sign in

Join the Newsletter

Get curated principle breakdowns + examples when we release new material.

UX
UI
UXUI Principles
All PrinciplesAboutTermsPrivacyCookiesRefunds

© 2025 UXUI Principles. All rights reserved. Designed & built with ❤️ by User Centric Studio LLC

PrinciplesParts
←Home/All Parts
Part 2 of 6

Core Principles

Core UX/UI Principles: The Must-Know Rules for Every Designer

What You'll Learn

Design Fundamentals

Universal design principles that apply across all interfaces and contexts. Master the fundamental heuristics that create predictable, learnable, and delightful user experiences through consistency, feedback, and user control. These time-tested principles form the backbone of usable interface design, providing a framework for evaluating and improving any digital product. Whether you're designing a mobile app, web application, or complex enterprise system, these core principles ensure your users can accomplish their goals efficiently and confidently.

Fundamental Design Principles

Key Concepts:

  • Consistency and standards across interfaces
  • System feedback and status visibility
  • User control, freedom, and navigation
  • Error prevention and graceful degradation
  • Progressive disclosure and feedback loops

Usability Heuristics

Key Concepts:

  • Jakob's Law and familiarity principles
  • Aesthetic-usability effect
  • Flexibility and efficiency of use
  • Recognition rather than recall
  • Help, documentation, and error recovery

Why This Part Matters

Essential insights for designers, developers, and product managers

For Designers

Core principles provide a universal language for design decisions. They help you justify your choices, evaluate designs objectively, and create interfaces that users intuitively understand. These heuristics serve as a quality checklist for every screen you design.

For Developers

Understanding these principles helps you build interfaces that behave predictably and handle edge cases gracefully. You'll make better decisions about error handling, state management, and user feedback mechanisms that align with user expectations.

For Product Managers

Core principles offer objective criteria for evaluating design quality and prioritizing improvements. They help you articulate why certain design approaches work better than others and provide a framework for making trade-off decisions.

Learning Path

30 principles organized into 2 chapters

1

Fundamental Design Principles

16 principles

2

Usability Heuristics

14 principles

30Total Principles
2Chapters
13minAvg Per Principle

How to Approach This Part

Tailored learning paths for different experience levels

For Beginners

From Subjective to Scientific

Start with Consistency and Standards (C.1.1.01) and Visibility of System Status (C.1.2.01). These are the most fundamental principles that you'll encounter in every interface design project.

For Intermediate

From Guesswork to Guidelines

Focus on the more nuanced principles like Jakob's Law (C.2.2.02) and Aesthetic-Usability Effect (C.2.2.01). Study how top products apply these principles in practice.

For Advanced

From Features to Outcomes

Explore the tensions between principles (e.g., consistency vs. flexibility) and learn when to prioritize one over another. Conduct heuristic evaluations using these principles as your framework.

Explore Core Principles Principles

Real-World Applications

Where to apply these principles in your daily work

  • •Heuristic evaluations and usability audits
  • •Design system development and guidelines
  • •User interface patterns and component libraries
  • •Quality assurance and design reviews
  • •Onboarding and user guidance systems
  • •Error handling and recovery flows
  • •Cross-platform design consistency
  • •Accessibility improvements

Practical Exercise Ideas

Apply what you learned with these exercises

1
Heuristic Evaluation

Evaluate your current product against all 30 principles

2
Principle Prioritization

Identify which principles are most critical for your context

3
Competitive Analysis

Compare how competitors implement these principles

4
Before/After Studies

Document improvements when applying core principles

5
Design Reviews

Use these principles as a structured review checklist

Prerequisites

Recommended knowledge before starting

Recommended Foundation
Part I

Foundations

especially cognitive load and mental models

While you can start here, understanding the psychological principles from Part I will deepen your comprehension of why these core principles work.

View All 30 Principles