wow didnt even know this exisisted!! the main thing we do is:

we pay our mortgage fortnightly (not monthly) means you pay an extra payment a year, we also pay a little bit extra than we are meant to (only an extra $100 a month) by doing this we have cut 10years off our mortgage. plus we put all our bill money for the month and a little extra into the offset account. means we get charged less interest too. and we can always get some money out of that in an emergency rather than having to charge our credit card.