To put it another way, when you vote: don't vote for your own tax cuts at the expense of lower income earners; don't vote for your own comfort at the expense of the homeless or the disabled; don't vote for your own culture at the expense of the immigrant and the refugee; don't vote for your big plasma TV at the expense of the environment; don't vote for the economy at the expense of society; don't vote for you at the expense of people who need help.
Vote with enlightened social interest, not enlightened self interest. Vote for the common good, not your individual good. Vote for the benefit of the least in society.
All of these sound like great aphorisms and you could probably feel good about dismissing them because of that structure. But you shouldn't. You should follow them because that is the measure of our society and the measure of us as individuals. If you're Christian you'll know that
"Religion that is pure and undefiled before God, the Father, is this: to care for orphans and widows in their distress, and to keep oneself unstained by the world." James 1:27The world would have you vote for yourself. It would tell you that you should vote for the people who will give you more money or make your house cheaper. Don't be stained by that. Instead, look after the people who need the most help. Look after them with personal actions and look after them with electoral actions.
And whether you're a Christian or not, you'll know that in Australia middle income earners are unaffected by a change of government. However, low income earners are always affected. Services are always changed after an election, moreso after a change of government. Some services are cancelled. Some are strengthened. Some are added. The people who need those services the most are low income earners.
So when you vote, change your mindset about who deserves the benefit of your vote. Think about the policies for the parties, not about how they affect you alone but how they affect the least in our society.