LinuxPlanet has a nice article with some tips for efficient OpenOffice (Writer) usage.
I always recommend continually saving with a new filename if you're working on a big document, e.g. Important00, Important 01, (...). This means that if your current document should for some reason get lost (which happens a lot with MS Office, but rarely with Openoffice), you can use the last save. I actually had Openoffice corrupt a document once I think.