Some traders use indicators like the Moving Averages, others use oscillators some just set support and resistance levels through Fibonacci retracements: whatever you use, I recommend that you look at historic price levels going back as far as your monthly charts go on each pair you trade in order to see where price is in relation to its long-term history. Whatever you choose, there will always be times when your approach/strategy fails, and your only hope there may be having a stop loss in place...