There are a lot of blogs out there that look great but they load very slowly.
The load time of websites is one of the most important factors affecting its usability; most Internet users will just skip a site altogether if it fails to load within a couple of seconds.
The longer your blog take to load the more people will just skip your site, so the load time of your blog is one of the most important factors affecting its usability.

Here's a list of 10 tips to speed up your blog:

1. Install Wp-cache plugin.
Go static. There are MANY techniques out there to handle things like digg and slashdot. A cache server/repository, load balancing, gzip compression on content, opcode cache for PHP, etc.
WP-Cache is an extremely efficient WordPress page caching system to make your site much faster and responsive. It works by caching Worpress pages and storing them in a static file for serving future requests directly from the file rather than loading and compiling the whole PHP code and then building the page from the database.
Download

2. Save Your Images for Web
One of the biggest mistakes people do is that they save the images in Photoshop the regular way.
Always use the “Save for the web” feature included on almost imaging software. In Photoshop just press Ctrl+Shift+Alt+S
I recommend saving your images in the PNG format which is very similar to GIF but it supports more colors.

3. Reduce Http Requests
Every HTTP request, or loading each item on your website, has an average round-trip latency of 0.2 seconds. So if your site is loading 20 items, regardless of whether they are stylesheets, images or scripts, that equates to 4 seconds in latency alone (on your average broadband connection).
The first step to reduce the delay from HTTP requests is to reduce the number of objects on your website. Get rid of unnecessary images, headers, styling features and the like. If possible you can also combine 2 or more adjacent images into a single one.
Secondly you should use a single one with all the styling information.

4. Optmize Your CSS
When you use a template there are many lines of code in the css for specific plugins, plugins maybe you will never use them.
Remove that unnecessary code.
Clean your Css and remove white spaces. Use CleanCSS online tool to do that. It will merge similar selectors, remove useless properties and remove the whitespace from your code.

5. With www and with /
When a user opens a link on the form "http://www.yourblog.com/about" the server will need to figure what kind of file or page is contained on that address.
The same thing with the www and non www.
All you have to do is to copy the following lines into the .htaccess file:
RewriteCond %{HTTP_HOST} ^yourblog\.com [NC]
RewriteRule (.*) http://www.yourblog.com/$1 [L,R=301]
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ^(.*)$ http://www.yourblog.com/$1/ [L,R=301]

Doing this you will have 2 things to earn: speed, removal of the duplicate blog content from the search engines.

6. Use Height and Width Tags
Many people tend to forget to use these important tags. These tags tell your browser the image size and he caries on with the rest of the content.
If these arent set, it will try to figure them out and that means loosing time.
Plus you will get a better image indexation if you use the height and width tags.

7. Compression
Along with reducing HTTP requests comes decreasing the size of each request.
If you run WordPress, you can save 20kB or more by enabling WP Admin » Options » Reading » WordPress should compress articles (gzip) if browsers ask for them. Keep in mind, however, that if you receive mass traffic one day you might want to disable that setting if your webhost gets easily ruffled with high CPU usage.

8. Avoid Javascript
Avoid Javascript as much as you can. Many javascript scripts will slow your site. If you can, avoid them because google doesn't like them either.

9. Disable Unused Plugins
Disable any plugins that you currently don’t utilise in the plugins section of wordpress. It’s easy to leave 30-50 plugins active even when you’re not using them simply because most webmasters will try out so many different versions of a particular plugin.

10. Optimise your Mysql Database
Optimising your Mysql database is pretty easy:

   1. Log into PHPMyAdmin
   2. Locate your Wordpress DatabaseTables
   3. Make a Backup First
   4. Check all the tables in the Check Boxes
   5. Select the Optimise Tables Option
   6. That’s it!

written by Florin C.