• Understanding UI and UX
• Understanding the Architecture of a Client Side Application
• Works effectively with Product Team Members, Designers and Back-End Developers

• In Rails use @imports for Sass files and not the asset pipeline
  
• Use @extend and @mixin to clean up and modularize code
• Use extend to inherit base styles from another class
  
• Use a mixin to inject a custom set of styles based on arguments.
  

• Use a CSS Pre-processor
• Sass, SCSS, or Less 
• CSS Resets or Normalize.css
• Resets provide a clean slate
• Normalize provides a default look and feel
  
• Style guides
• Good for multiple developers
• Helps you create a disciplined style and structure
  

• Elements Inspector
  
• View, add, or edit the HTML markup and CSS Live
  
• Debugger
  
• Set breakpoints and step through your code
  
• Javascript Console
• Log diagnostic information
  
• Interact with the document and evaluate expressions
  

• Network Tab
• Tracks the load times for each asset on your page
• Audits
• Gives optimization hints and points out unused CSS
• Pagespeed / Yslow
• Grades the performance of the web page, and leaves tips for improvements

• Virtualbox, BrowserStack, Browserling
• CanIUse.com, html5please.com
  
• Use Polyfills
• Respond.js
• Fixes Media Queries in IE6 - IE8
• Selectivzr.js
• Enables Legacy browsers to use CSS3 selectors

• Style Guides
• Books
• Courses

• Thoughbot SCSS Style Guide
  
• Github CSS Style Guide
• Google CSS Style Guide
  

• Visual Grammar by Christian Leborg
• Scalable and Modular Architecture for CSS
• JavaScript: The Good Parts
• jsbooks.revolunet.com

• CodeSchool
• Fundamentals of Design

• http://css-tricks.com
• http://codegeekz.com
  
• http://www.css3.info/
• http://gun.io/blog
• http://nettuts.com
  

Forums

• https://developer.mozilla.org/en-US/
• http://www.webplatform.org/
  

Compatibility Checks

• http://caniuse.com
• http://www.quirksmode.org
• http://html5please.com/
  

• http://www.99lime.com/elements/
• http://draeton.github.io/stitches/
• http://usablica.github.io/front-end-frameworks/compare.html
• http://list.ly/list/303-alternatives-to-twitter-bootstrap-html5-css3-responsive-framework
• https://github.com/thoughtbot/flutie
  

Randoms

• http://roole.org/
• http://www.limejs.com/
• http://yepnopejs.com/
• http://yeoman.io/
• http://xdk-software.intel.com/
• http://www.appgyver.com/
• http://hellohappy.org/css3-buttons/