It's about optimizing your scripts, Warband scripts and data send scripts. Most commonly used is PHP.
Since I don't know that much sbout Warband scripting. I'll talk about PHP and some tricks.
You can do some tricks eith the .htaccess file, making it so that the request itself (Url) doesn't have to be received by the server first, basicly making it a shortcut. This won't help alot but every bit helps.
Never use seperate files for sending DB information.
For instance:
Bank.php
Save.php
Welcomemsg.php
This makes the server open the whole file for maybe only one player every 10 seconds. If you would use a neat feature in PHP for instance:
If(isset($value))
{
//code
}
Or
$action
If($action=='1')
{
//code
}
This makes the web server handle every request making it more efficient.