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
Gambling it , Easiest way to make that double , 
If you are going to double that in 1 day play gambling and stay there until you play more than hours trading can't help you to earn bitcoin a month coz it takes more month before that coins will rise.and if you are going to invest that you only get 1% to 3% in investing.