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
it depends on what knowledge and skill you have such as knowledge of trading, signature campaign, mining, etc or skills you can offer such as translation, video/photo editing, etc.
Signature campaign and mining cannot generate that much profit for anyone in a month, though trading and selling services may take you near your target, but it is still hard because 0.5btc is not a small amount to be earned.
If you have good skills in trading that you can expect to earn that amount in a week or at least in a month and once you get expertise then sky is the limit for your earnings in trading.