Step one: https://shapeshift.io/
Step TWO: put Steemit on the left bar and Bitcoin on the right clock Continue ( as shown in the picture )
Step three: send the steemit coins promptly as instructed ( make sure you also but you Bitcoin address in the receive bar and your steemit username in the "send back" bar, this way if there were to be errors, they can correct it faster but I've had smooth sailing with these guys )
Step four: watch the website convert and enjoy your bitcoins!!!
P.S. https://bitpay.com/ can send you a prepaid debit card you can load your BTC onto and spend like cash