Watch Commodity Prices while Trading Currenciesby Kathy Lien
If you want to trade commodity currencies, the best way to use commodity prices in your trading is to always keep one eye on movements in the oil or gold market and the other eye on the currency market, watching how quickly it responds. Due to the slightly delayed impact of these movements on the currency market, there is generally an opportunity to overlay a broader movement that is happening in the commodity market to that of the currency market. Bottom line, it never hurts to be more informed about commodity prices and how they drive currency movements.
Source: http://www.investopedia.com/articles/forex/06/CommodityCurrencies.asp; http://www.bktraderfx.com/site/members-benefits; http://www.gftforex.com/