Tax question: My Kindle publishing revenue is being taxed 30% by the US gov. Do i still need to be taxed or even declare my earnings in my country?

I'm a newbie entrepreneur living in Malaysia and i don't knw a whole lot about taxes because i'm not employed by a huge corporation. I make a living with my online revenue. Does double taxation agreement apply? where i don't have to be taxed again? if yes, do i still need to declare? What are the white and grey areas on this? I don't want to break the law yet i want to knw the current loopholes of earning an income that is already being taxed outright @30%