When a doji candlestick is spotted in the market, first look back to see if there has been enough movement for you to benefit from a retracing. A retracing may only be about one 3rd of the distance since the last low. If that gives you sufficient room to cover your spread and make allowance for a little slippage, you can go on to step 2.
Step two involves checking an oscillator to be certain the current price is shown as overbought or oversold. An overbought or oversold market and the doji is a pointer that you can get involved. You may also glance at the trading volume. If trading is trailing off, then this is another sign a reversal might be about to happen.
When you open a trade, be prepared initially for a reversal. Either set a limit order at the point that you would expect a short term retracement to reach, or watch and do this by hand. With the other half, you could move the stop to a no-lose position close to your opening price, and let it run in case a major reversal happens.
Of course, there is always a risk, as with any form of hopeful trading.