Practice a little.
Build a lot.

JSON (RFC 8259) is the universal data format for modern web APIs. Standard JSON allows 6 data types: string, number, object, array, boolean, and null. Keys must be double-quoted.

• No functions, undefined, BigInt, or trailing commas are permitted in valid JSON.
• JSON.stringify() automatically omits undefined properties and serializes undefined array items as null.
• Revivers and replacers in JSON.parse() and JSON.stringify() provide powerful custom transformations.

Modern ECMAScript powers both browser interactions and server runtimes. Mastering closures, prototypal inheritance, and the asynchronous event loop is vital for web development.

• let and const provide block scoping and reside in the Temporal Dead Zone until initialized.
• Promises and async/await leverage the microtask queue, which executes before macroscopic macrotasks like setTimeout.
• Strict equality (===) prevents implicit type coercion, ensuring safer comparisons across application state.

React builds declarative user interfaces through components, virtual DOM reconciliation, and hooks. State immutability and pure rendering prevent bugs.

• State updates in useState should be treated as immutable to guarantee accurate re-renders.
• useEffect isolates side effects, and clean-up functions prevent memory leaks and orphaned subscriptions.
• Keys in list mapping must be unique and stable across renders to preserve component state and DOM integrity.

Next.js enhances React with hybrid rendering: React Server Components (RSC), Client Components, streaming with Suspense, and edge caching.

• Server Components render strictly on the server and transmit zero JavaScript bundle size to the client.
• The 'use client' directive marks the boundary where client-side interactivity, hooks, and browser APIs begin.
• Next.js route handlers and server actions streamline data mutation without external API boilerplate.

Semantic HTML and resilient CSS form the backbone of web accessibility, SEO, responsive mobile design, and fast Core Web Vitals.

• Semantic elements (<main>, <article>, <nav>, <header>) empower assistive technologies and search engine crawlers.
• CSS Flexbox excels at 1D content alignment, while CSS Grid handles complex 2D responsive layouts seamlessly.
• Accessible color contrast ratios and visible keyboard focus outlines ensure compliance with WCAG standards.