There is a saying, the chance favors the prepared mind. Hence, you must balance opportunity with risk management. A way to measure risk to decide the trade size. You can maximize your chances of winning by combining both fundamental and technical analysis.
In ranging situations, you should aim for a risk to reward ratio of 1:2. In trending situations, you should aim for a risk to reward ratio of at least 1:3. Also, you should be aware of the profit to loss ratio of all of your trades. Cut your losing trades by using