Originally Posted by Brujah

Use a cache plugin, like Super Cache, or other.

Turn off post revisions if you don't need them.

Install a database plugin like WP DBManager that will optimize your tables every week or month if you tell it to. It also backs them up and can gzip and email them to you each night if you want. I have all of mine backed up this way each night and sent to a Gmail account. With Gmail I have them filtered straight to the Trash, knowing that Gmail keeps them there if I need them for 30 days.