invest to hyip. 
One of the best way to grow your bitcoins IF you know where , when, and how much you'll gonna invest. It requires to be a risk-taker though cuz anytime you can lose your BTC but if you are keen in looking for a good and stable HYIP, you'll definitely gain high and quick profit. But as I always say, it's not recommended especially to bitcoin newbies
so can i ask if you have any HYIP that gives you gd returns or profit so far?? is it a long term investment for you or a short duration investment??
don't even think about using a hyip because the chances of getting back your money + profit is one in a million. hyips are practically a gamble with terribly low chance of winning.
i am sure that you have better chance of doubling your coins in gambling dice but not in hyip.