Depend your strategy, because every strategy have different rules. For day trader you need 0,01 btc, short time period with extra time for watching market. But if you're long period trade you'll need 1 btc, because martiangle is their strategy. Why you not try with demo account, is good to test our strategy. Prepare with a good plan before trade on real market. Get profit with real money on real market is never easy. Good luck.