If you want to get a profit, well, that's a basic strategy for traders " Buy low, Sell high " but everyone has a different strategy how they trade their coin. Anyways, for me my own strategy is when i buy the coin and if i know that i gain, i sold it if its not i hold it when the market increase again that the time that i sell it all, and i don't want to put my money in one basket 'cause i want to diversify my investment.