Today I found a great article for best practices for making web pages fast. The list includes 34 best practices divided into 7 categories.
Content
- Minimize HTTP Requests
- Reduce DNS Lookups
- Avoid Redirects
- Make Ajax Cacheable
- Post-load Components
- Preload Components
- Reduce the Number of DOM Elements
- Split Components Across Domains
- Minimize the Number of iframes
Server Side
- Use a Content Delivery Network
- Add an Expires or a Cache-Control Header
- Gzip Components
- Configure ETags
- Flush the Buffer Early
- Use GET for AJAX Requests
CSS
- Put Stylesheets at the Top
- Avoid CSS Expressions
- Choose over @import
- Avoid Filters
Javascript
- Put Scripts at the Bottom
- Make JavaScript and CSS External
- Minify JavaScript and CSS
- Remove Duplicate Scripts
- Minimize DOM Access
- Develop Smart Event Handlers
Cookie
- Reduce Cookie Size
- Use Cookie-free Domains for Components
Images
- Optimize Images
- Optimize CSS Sprites
- Don’t Scale Images in HTML
- Make favicon.ico Small and Cacheable
Mobile
- Keep Components under 25K
- Pack Components into a Multipart Document
For details, check out this.