You need to merge EUR/AUD and AUD/USD with EUR/USD and watch for a sharp spike (up or down) in EUR/USD .
If the same spike occurs on EUR/AUD without occurring on AUD/USD (or vice versa) then in most cases it suggests that either EUR or USD is spiking alone and the chance of correcting back-fast is far more probable than normally. This occurs just few times a day, but with patience it can be very profitable for scalpers. You can also use Dollar Index for comparison, but I found AUD comparison to be far better.
Head over to the next chart linked bellow for more details and let me know if you have any questions.
Sometimes I really on the spike alone, I enter as soon as it seems excessive compared to the overall price movement. Rarely do I enter at the highest/lowest point. It's impossible to predict exactly at which point will the price bounce back, but that's not necessary to make a profit. If the price continues without a bounce, there's still a chance it will at least bounce back to your entry point where you can hedge and minimize the loss. Also, if the price bounces, but then returns to the level of your entry, you should hedge as well because the bounce should go straight back. If it oscillates, then it might just be a short correction before the full breakout.
You also have to watch for news releases, if EUR or USD had a news release around the time of the spike then the whole strategy is irrelevant.
This method can also be used to spot fakeouts when trading breakouts. Breakouts don't happen unless EUR and USD act together.