Pick a rule. Any rule. See what really decides the outcome.
Choose a moving average between 5 and 30 days, and an RSI level between 60 and 75. Buy when price closes above the line, sell when it closes below. There are millions of variations and plenty of them work. Run one on real history, then look at what happens when the same rule is followed by someone who hesitates.
Most traders don't lose because the indicator was wrong. They lose because they abandon the plan — hesitating to buy out of fear, refusing to sell out of greed. Run a few variations here and you'll notice something: the numbers move around, but the gap between following the rule and half-following it is almost always bigger than the gap between one rule and another.
Past results don't predict future ones. This is a study tool, not advice.