Success in any kind of operative mainly requires good timing, but success in short term trading requires perfect timing.
For perfect timing, we need to understand how price moves in financial markets.
The core principle is that in the market there is always the same number of buyers and sellers; for someone to buy, there must be someone to sell to.
The price is moving by searching for liquidity.
Large traders need to find other traders with whom they can place orders when opening and closing trades.
These are areas where price naturally turns; previous highs and lows.