Extend laptop battery life in Linux?

I came across a thread at the Debian User Forums a while ago on this subject. One post there suggested installing TLP.

The Mint Guide suggests you need to run 

# tlp start

once to start it.

I don't use my laptop very much at the moment so I haven't been able to test it. At some point I will try to get round to doing a test and post an update, but if you find laptop battery life is poor compared to Windows, maybe try this.