How can we make ethical choices in a consumerist economy?

So, in the last few days I have read a few things, including this Guardian article. As much as I agree with the anti consumerist message, I feel that it's a little too harsh on us 'consumers'. Yes, we all probably could and should buy less but the article falls short in the respect that most people do not know HOW to buy less. Particularly when it comes to things we need. The other thing I read yesterday was that the number of disposable nappies in this county alone is in the millions. And wipes are littering our beaches. For those of us with small children, nappies are essential. I, for one, am not convinced that buying a load of reusable nappies, hot washing them and tumble drying them is a suitable alternative to disposal nappies. I personally think that the government should implement legislation to prevent companies from over packaging food, stop the use of polystyrene and other non recyclable packaging material and encourage fast food outlets and supermarkets to use corn starch bags and other biodegradable alternatives. How else are consumers supposed to make green choices if there aren't any options worth choosing from?