Reduce Critical path loading and unnecessary script blocking.
Leverage async and defer load where possible
Tree-shake bundles and eliminate loading of dead or unused code
Improves page load and overall UI performance. Improve Caching & reduce bandwidth usage
Defined performance budgets & adhere to them
Set Performance goals Setup ongoing measurement & monitoring tools for reporting Establish escalation processes for performance guardrails & remediation
Follow web API, platform best practices & leverage native web APIs when possible
Monitor emerging capabilities & UI best practices through MDN and W3C Stay UpToDate with cross-browser support on emerging specs and XE support. (caniuse.com)
Reduce complexity, Adopt frameworks responsibly
Framework adoption should always be weighted against the complexities & requirements. Use frameworks only when solving complex UI/UX problems. Do not adopt frameworks without a business need. Always Leverage native browser capabilities over framework adoption. This will reduce complexity & leads to performant UI with a maintainable code base.
Follow Web Content Accessibility Guidelines (WCAG) 2.0
https://www.w3.org/TR/WCAG20/ Test UI with Screen Readers on Mac (Voice Over) and PC (NVDA) Test UI Designs against for contrast ratio guidelines https://webaim.org/articles/contrast/