Do you want to speak English with American accent?!
It is very simple!
You should find an American teacher for your self!
But if you can not find an American teacher, Don't Worry!
Here I will introduce you a very good website for learning English with American accent!
It is https://www.eslpod.com/ which helps everyone to learn English.
This website managed by Dr. Jeff McQuillan.
In this website you can find very useful podcasts in different levels.
Go to this website and then start listening to the podcasts regularly.
The Most important thing about these podcasts is that all of them are included with transcripts!
So you can download podcasts into your mobile phone and read their transcript as well.
Cheers!