Betting in-play should only take place when you want to either lock in profits or you see a major market mistake. So follow these rules to make sure that your strategy does not impoverish you.
1. Have a bank roll which is not pressure money, and only risk a maximum of 5% of the bank roll on an event.
2. Do research of each market making sure you follow the market closely.
3. Make sure you are actually watching the event without a serious delay. A delay of more than 5 seconds is not recommended.
4. Never chase losses.
5. Try to know something of the sport you are following. Even traders must have some knowledge of the rules and regulations.