In magento you can improve website speed by doing some small tricks, Below are the 5 Different techniques to boost magento site, Just do the following steps to achieve it:

1) Enable Flat Categories and Products Options: Go to the Magento Admin section System->Configuration->Catalog->Catalog set "Use Flat Catalog Category" and "Use Flat Catalog Product" to yes .

when attributes(applied to product and category) are stored in separate tables , but when we enable these Flat options it will put all attributes in one table for Magento to retrieve data, so it will improve speed performance.

2) Merge CSS and JS : Go to the Magento Admin (top menu) System > Configuration, Advanced > Developer, (main page) JavaScript Settings, CSS Settings. Set Merge JavaScript Files and Merge CSS Files to Yes.

Doing this steps will make magento to put css and js into one file os in each page in magento will load fast.

3) Enable Compilation : From Magento admin Go to the System > Tools > Compilation and Enable it. it will take all the active scripts in Magentos core structure and bring them in one directory.

Code Compilation does not convert PHP code into native machine code but it put PHP code into a single location that is in "includes/src

when you update code or doing modifications, extension compilation has to be disabled first.

4)Add Expires Headers: The web browsers use expires headers to set how long to catch a particular type of media

The best way to use these headers is a .htaccess file where you can adds some configuration to your server.

<ifmodule mod_expires.c="">
  ExpiresActive on

# Your document html
  ExpiresByType text/html "access plus 0 seconds"

# Media: images, video, audio
  ExpiresByType audio/ogg "access plus 1 month"
  ExpiresByType image/gif "access plus 1 month"
  ExpiresByType image/jpeg "access plus 1 month"
  ExpiresByType image/png "access plus 1 month"
  ExpiresByType video/mp4 "access plus 1 month"
  ExpiresByType video/ogg "access plus 1 month"
  ExpiresByType video/webm "access plus 1 month"

# CSS and JavaScript
  ExpiresByType application/javascript "access plus 1 year"
  ExpiresByType text/css "access plus 1 year"
</ifmodule>

5) Use GZIP compression : We can control the number of bytes sent over the network by using GZIP compression, using GZIP compression we can reduce the size of HTML, CSS, and JavaScript files and can reduces download time .

6) Use Memcached : Memcached is a high-performance, distributed memory object caching system, its is generic in nature but originally intended for use in speeding up web applications by reducing database load. In Magento system Memcached is not enabled by default, so to use this you need to start the service and then restart Apache.