Where should place a stop loss while trading

A stop-loss order is only an order that closes your position at a particular cost. It controls your risk by limiting your loss at that price.
If you buy a stock for $ 20 and decided to give a stop loss at $ 19.00 when the price reaches $ 19.00, then your stop loss order will be executed, and it prevents further loss.

Stop loss orders are normally a "market orders," meaning it will take whatever price is available once the price has reached $19.00 can be based on the bid, ask or last price touching $19.00).If no one is able to take your trade off your hands at that price You can end up with a worse price than you expected.this is referred to as slippage.
Unless you trade stocks, currencies or futures contracts with high quantity, slippers are not an issue, while the business of the day is generally not an issue.

1 When Buying Where to Place a Stop Loss Order

A stop loss should not be kept at a random level. The ideal place for stop loss is in one place, which allows the market to fluctuate in a sufficient room for a little, while it starts moving forward in your favor, but if the price goes against you, get out of your trade. One of the simplest ways to put a stop loss during buying is to keep it under "swing low".A swing low happens when the price falls and after then bounces. It shows the price which is to be found at that level.
You want to be do trading in direction of the trend. The swing lows should be moving up, as you buys.
The chart probably shows several possible entry points with stop-loss locations for each entry.

2 When Short Selling Where to Place a Stop Loss Order 
A stop loss should not be kept at a random level. The ideal place for stop loss is in one place, which allows the market to fluctuate in a sufficient room for a little, while it starts moving forward in your favor, but if the price goes against you, get out of your trade. One of the simplest ways to put a stop loss during short selling is to keep it over the "swing High".
A swing high happens when the price increases and then falls. It shows that the price is resistant at that level.
The Swing highs should be moving down when you looking for short trades.The chart probably shows several possible entries with stop-loss locations for short
trade. 

3 Define your stop loss strategies
 
Stop loss levels shouldn't be put at random locations. Where you keep a stop loss is a strategic choice, and it should be examining and practicing several methods and based on what works best for you. A trading plan is where you define the all important things like how will you enter trades, control risk, and exit profitable trades.Use trade in the direction of full trends, and use a simple stop loss strategy that provides sufficient room to move forward in your favor, but if the price moves against you, then it cuts down your losses rapidly.