How can I make minimum of 0.3btc in a month without trading and gambling?
As I've heard bad experience with both, but still need to make money
Try to join some campaign here in bitcointalk and create many accounts. Join your accounts to different campaign and use only one wallet or it depends to you. You need to exert more effort and time in order for you to earn a fair amount of bitcoin you want in a month. Also, be patient. You cant have money in an easy way.
For addition in joining signature campaigns in bitcoin, make your post in good quality and constructive when making your rank up. That way, it is easy for you to accept in the campaign and receive high income. The salary receive depends also on the rank. Look for good campaign and work hard on that.
Assuming a Full member status and signature campaign paying 0.006 BTC/week for 25 messages. You need 12.5 full member accounts in order to achieve the goal.
That is 1250 quality posts in four weeks (or 42 messages a day)!
Even if you double the weekly rate for a Senior member, you still need about 600 quality messages in order to achieve the set income. Good luck OP.