Er, I don't think there's much you can do.
It depends how much you value your sanity. Depending where in NW London, you could reduce the cost by taking the teeth-rattling slow train to Waterloo, change at Clapham junction and then get onto the Watford train, thus missing out zone 1 and this'll knock the price down a bit.
Either than that, I do know somebody that goes on the bus (
www.nationalexpress.co.uk) every day, but he's almost zen-like in his calm.
Or, you could get an annual ticket. Which works out cheaper, but you need to remorgage to afford the upfront cost.
They've put up barriers at Reading now, so the suggestion I couldn't possible make about not paying and just dealing with the fine when you get hit once a month, doesn't work anymore......