You can start earning from signature campaigns, if you have higher rank accounts then that will be added advantage for you and you need to join campaign with higher pay outs.
even if someone has higher rank, he can't be able to earn 0.5 bitcoin in a month. unless he has more then one account.
I think the only way to get 0.5 bt in a month is trading (if you know the best time to buy and sell, but it needs years to learn this skill).