When it comes to trading foreign currency, you use a forex broker, also known as a currency trading broker, to place your trades. When you trade forex, you buy or sell in currency pairs, e.g. "EUR / USD" (Euro / U.S. Dollar). You open an account, deposit funds, then use the broker's trading platform to buy and sell currency using margin. Forex markets are open 24 hours a day, five days a week. For learning the basics, we recommend the School of Pipsology or the NFA's Trading Forex booklet.
The Aussie dollar is very dependent on the price of gold, as Australia is the 2nd largest gold producer in the world. If gold prices fall, this means Australia is getting less money for that gold, and generally the Aussie dollar will weaken in these circumstances. If gold prices rise this is great for Australia and their dollar will normally strengthen with the rise in the price of gold.
Interest Rate Risk: The moment that a country’s interest rate rises, the currency will strengthen. The boost in strength can be attributed to an influx of investments in that country’s assets since with a stronger currency, higher returns can be more likely. But if the interest rate falls, the currency will weaken, which may result to more investors withdrawing their investments.
By contrast, if you just traded 20 EUR, a loss would not significantly affect your account balance. It would provide you with the opportunity to learn from your experience and plan your next trade more effectively. With this in mind, limiting the capital you are prepared to risk to 5% of your account balance (or lower) will put you in a better position to continue trading Forex (and improving your technique) over the long term.