I heard in stocks, this is called shorting. But i read if you short, you could lose a huge amount of money. Could you do this with bitcoin? Example my thoughts were hey its the holidays, so most likely ppl will withdraw money and thus btc drops. So i figure around now, btc price would drop.
I think you use momentum strategy to get income, no big deal but I'm afraid every momentum has different impact ( not always same ). Use momentum strategy need big money and fundamental analysis to get good analysis. I'll not teach you about it but how about you try it by your self and see what happen. Not always work but you can learn something.