The most useless things are probably those learned the first years: candlestick patterns, classic technical analysis (triangle etc.)
They probably worked in the 1990s, with few players.
Then I would not spend time searching for the best indicator, best oscillator, and best strategy with 100% profit (as all new traders do the first years). The best indicators/oscillators are the most used ones (MA, RSI, MACD, etc.). The "alternative oscillator" is alternative for a reason.
I value most the fact that all strategies work better on higher timeframes. 1 minute to 30 minute timeframes tend to give too many false signals.