1. Identify a person who you want to sound more like (an English-speaking actor, for example).
2. Listen to them say a phrase.
3. Record yourself while you mimic the way they say the phrase.
4. Check the recording and then return to 3 until you are satisfied.
5. Return to 2.
You don’t even really need a recording; you should be able to tell just by listening to yourself speak. A recording will help you understand how other people hear you speak though, and is more precise. I expect you would see significant progress in only a few hours.
I suggest a fast and cheap procedure:
1. Identify a person who you want to sound more like (an English-speaking actor, for example).
2. Listen to them say a phrase.
3. Record yourself while you mimic the way they say the phrase.
4. Check the recording and then return to 3 until you are satisfied.
5. Return to 2.
You don’t even really need a recording; you should be able to tell just by listening to yourself speak. A recording will help you understand how other people hear you speak though, and is more precise. I expect you would see significant progress in only a few hours.