Stop placement is an analytical decision, not a financial one. The level should mark the point at which the reason for the trade no longer holds - below the pivot, beyond the range edge, outside normal atr noise.
The common error runs the logic backwards: deciding to risk $300, dividing by a comfortable share count, and putting the stop wherever that lands. The result is a level with no meaning, which the market visits routinely. Correct order: level first, stop-distance second, size third, and if the size that falls out is too small to be worth trading, skip the trade instead of tightening the stop.
Placement also needs a buffer. Stops sitting exactly on obvious round numbers and prior lows cluster with everyone else's, and clustered liquidity attracts exactly the probe you are trying to avoid. A few ticks beyond the obvious level costs little and avoids a large share of avoidable exits.
Related: stop-distance, volatility-stop, hard-stop, stop-hunt