1. If the stock has some fundamental problems, best is to just cut loss immediately and wait for it to bottom out and has a reversal to consider it again. preserving your capital is most important.
2. Averaging down is not a good idea because you will have over exposure on a single stock.
3. if the stock is fundamentally a good stock but down on external market environment, you can always sell put to protect the stock and make a little income while waiting for it to recover.
4. There are so many stocks one can buy so never fell “in love” with a stock, it is only an investment!