Drupal tips

Here are a few things that I have learned over time

• Only enable needed modules - tons of modules are available and although it can be fun to enable everything for experimentation, the more modules are enabled, the slower Drupal will run and the more ressources it will need. Further, the more modules are enabled, the more potential security holes exist. Also, more modules means more user confusion, especially if the final admin is not very technically oriented
• Make sure Drupal is updated - as mentioned in the previous point, security holes appear and you do not want your installation to be hacked (drush can help, see post on drush)
• Use Multi-Site feature over multiple installs - There are cases where maintaining multiple installs is necessary, such as multiple servers. However, if possible, group all sites under one install. It makes backup easier, and updates faster and simpler.
• Ensure a good default site exists - On multiple sites it may be tempting to put all the sites in site.com named folders but you never know when someone will come through a different path (such as accessing the ip address). It is important to have a valid default folder (maybe the most used site)
• If privileges not needed, disable it for day to day accounts - admin account can do a lot of damage (either accidentally or through hack). Create users with only needed privileges and use them. 
• enable social media interaction - allowing people to share pages is awesome and bound to bring traffic
• Removing modules - if you are about to uninstall a module, disable it first, uninstall from menu then clear cache. Otherwise trouble may crop up.
• Use sqlite to develop locally - Assuming that it is a small site that will have mainly read operations, use SQLite: enabling the site is as simple as copying the site folder to the target host. However, test first that  the   correct SQLite version is installed (Centos 5.5 for example doesn't by default)
• Use Admin menu module - it can make administration much more smooth.
• Enable anti-spam measure - Some spammers have automated tools to interact with Drupal. By enabling anti-spam modules on forms such as recapcha, you decrease (though unfortunately not remove) spam attempts.