Actually setting SL and TP at appropriate position is very tough for many traders. It mainly depends on your trading style and strategy. If you are a scalper then generally these values are very close to open price even you will find no SL in trades. And for swing traders it is at least 100 pips away from open. It can be around 500 pips or more for long term investor. Now depending on your trading style you need to choose yours. But it is necessary to give your trade a room of at least 50 pips before it hits the SL.