Those that tested multiple methods, what did you find as more efficient in terms of accuracy for day trading?
There is no consensus among traders even when they are all looking at the same chart. Therefore, each trader, by testing, chooses independently which indicator to use. But, as a rule, you should not use more than 3 indicators, otherwise you will see conflicting signals.
Also while indicators are calculated using different formulas most of them belong to the same family and they perform the same function.
An example of this are the SMA and the EMA, they have different formulas but at the end both are trending indicators, they smooth out the price action and give you a clearer picture of the direction the trend is taking, so it is not necessary to use both of those indicators on the same chart, you can pick the one you like the most and drop the other one and make room for another indicator which could make clearer another aspect of the market.