Making WordPress run faster

My wordpress page is loading relatively slower than anticipated. Even just changing pages to another page with little to no information takes more time that I would like. Changing the frontpage to load only 5 posts and disabling many of the discussion options has helped. We have yet to use WP-Cache. Are there any other tweaks to make wordpress more snappy? Do themes have anything to do with the sluggishness? Thank for any help.