remain the same: buy down sell up
The problem with "buy low sell high" is that after you sell high, Bitcoin often keeps going up and up and up, while you're stuck in fiat. And sometimes after you buy low, it keeps crashing.
When you are doing a margin trading, then yes, this will become a very big problem as your position might get liquidated, but if you are trading normally, not using any 'leverage' then you should be fine.. accept your loss and then trade for another day