The best way to gain accent is to do Shadow reading. I came to know about shadow reading while i was studying in british council. It is the method where you will have a text script of some audio and you have to speak aloud along with the speaker in the audio. You have to speak at the same time and pace , pause when speaker pauses, and speak when they speak. It is very good way of gaining native english accent. Personally i am happy with my accent. Because even many native speaker do not speak perfect englsih themselves. Many of them speak in a way which is not correct phonetically.