How long should you hold a stock before selling, if trading in the short-term?

I've recently brought a share but it has drop down in price. But from the strategy I'm applying, I feel that it will go increase as the professional traders have targeted it to increase but it hasn't done so far. I'm now thinking to sell it but feel if I do it will suddenly increase.

What the maximum time you should hold a stock before selling, if trading short-term?

How long should you hold a stock before selling, if trading in the short-term?