Can anyone suggest me some ways to earn 0.5btc in one month online...i know it is not possible with faucets..is there any other way

DO NOT listen to people telling you to gamble the money you have at the moment... that must be the worst option to chose, if you had to

pick a method to double your Bitcoin. The best method I had to double my coins, were to hoard it for a year. I bought at $200 and sold at

$600 a year later.... There are no guarantees that it will happen again, but I did it.. So, just hoard your coins and hope for the best. 

Yes bitcoin is a money and can you think about doubling your money easily,its not,so its not possible with bitcoins also.Yes you can double them at one stage if you can get some profit on trading or find some good earning work for bitcoin,but it will take a long time for not,doubling bitcoin quickly is not possible.

Never heard of it, so would never recommend it either. Rather look into a more trusted site.

I really hope this isn't a link spamming try.

Fastest and the riskiest way = Gamble it on a dice game with 2x payout. Do it only if you can afford to lose your btc. If you ask for safe way, trading might be the right thing to double your btc.