the easiest way is definitely to gamble it all and either win or lose everything though it is really risky to be honest
also you should try trading it and you will most probably earn some coins with it though it will be really slow
Gambling is not at all a good suggestion for turning 7 to 17 but it is good for making it from 7 to 2 or 7 to 0 though.
And trading will not earn you profits but will cause a big loss to you if you have no experience about it, and if you have some experience about trading then it can give you great profit and that profit is not slow at all.
Honestly speaking if I would be holding 7 btc at a moment then I would keep it safe for future without experimenting with it, and will sell at the time of halving to earn good profits.