A good indicator in forex trading should have characteristics such as accuracy, reliability, simplicity, versatility, compatibility, and timeliness. It should provide clear and actionable signals based on reliable data, with a proven track record of success. The indicator should be easy to understand and use, and work well with other tools and strategies. It should also be adaptable to different market conditions and timeframes, and provide timely signals that allow for quick decision-making. Ultimately, a good indicator should help traders make informed and profitable trading decisions while managing risk effectively.