Start with triggers and feedback. For every action, define what initiates it (click, tap, keyboard, voice) and how the system responds (visual change, motion, sound, haptic). Feedback should be immediate for recognition and paced for comprehension. Loading states need to appear within 100–200 ms; anything longer benefits from skeletons or optimistic UI. Use copy that explains what is happening, not just that something is loading.

Motion communicates cause and effect. Use easing curves that resemble real movement—ease-out for arrivals, ease-in for departures—and keep durations short (150–250 ms for simple UI changes). Animate properties that reinforce structure: opacity, scale, and position, not gratuitous rotations. Respect reduced motion settings and provide non-animated fallbacks. Avoid animating color only; it can create flicker and accessibility issues.

States are the grammar of interaction. Define hover, focus, active, disabled, and error across components. Ensure focus rings are visible at all times for keyboard and assistive tech users. For destructive actions, combine confirmation patterns with clear copy to prevent accidents. For success, provide quiet affirmation and a next step. Don’t trap users; allow undo where possible.

Progress is a promise. Use spinners for unknown durations and progress bars for known ones. Communicate what’s happening in plain language and allow escape hatches when possible. Avoid dead ends; after a task completes, orient users toward the next likely action with a gentle highlight or motion cue.

Accessibility is non-negotiable. Every motion cue should have a static counterpart; every color change should be paired with an icon or text. Provide generous hit areas and visible states for touch and keyboard. Announce dynamic updates to assistive technologies so screen reader users aren’t left behind.

Operationalize quality. Create a motion library with durations, delays, and curves; define sound design guidelines if audio feedback exists; establish a vocabulary for haptic patterns. Ship checklists that teams can run through during QA, and maintain examples that demonstrate good taste in context. When micro interactions work, people describe your product as “fast,” “clear,” and “pleasant.” When they don’t, they call it “confusing” or “laggy.” Mind the moments—they add up. Treat these moments as part of the core experience, not garnish.