Abhishek Gupta

I'm pretty sure, all of those people who suggested to watch movies they can't even speak English close to native speakers, and you'd believe it too. Just listen to this explanation.
Let's assume a scenario in which I told you to speak a word which is, "Antidisestablishmentarianism". Now let's be honest, you'd be having a lil bit trouble reading it at the first go but as soon as you check its pronunciation and after two or three shots you'd be able to speak it. But, if I say you to read this word "?????????????", its a Russian word for teacher, you won't be able to speak it even after having the pronunciation lessons. Why? Because you don't know the technique to make that kind of sound, most of these sounds are not even present in Hindi/English language.

Its the same thing with speaking like a native speaker. If you are going to watch movies and talk like them, it would be quite apparent that you're copying. Hence you will be disclaimed as the person with a fake accent.
So how to speak like a native speaker? If you really want to talk like them, then you should learn like them. Did you know there are 26 letters in the English alphabet but 47 different sounds including 15-16 vowel sound(more or less)? You've to get a good grasp on every one of it. And that's just for the starters. They excitingly use vocabulary, and it can seem unorthodox to us. So getting a deep understanding of basic and most common words would be your job 2.
Apart from that, you can do an awful lot of stuff which ain't probably possible. Not because you aren't a native speaker, but because your English exposure and involvement with the language are much less according to them.

I guess it did help some of you and didn't believe these people who are just brain farting anything. Only those people can teach English or, any language whatsoever well, who has a good understanding of linguistics as well as the fundamentals of learning a language.

One will find various sorts of answers to this question if they start exploring over the internet. Though my answer would be quite different from any of it and I'm just saying it out of my experience of teaching and learning.

A spoken aspect of English can be mastered in many ways, but the ones I find most effective are:
1. Having a clear understanding of functional grammar, just FYI, which is no the same thing as regular grammar. And by grammar, I don't mean every section of grammar like Verb advanced or Speech, Narration; instead, I'd emphasize the primary sentence structuring and formatting. If you can make correct structures in your mind the very moment you have to speak it, more than most of your work is done right there.
2. Having a thorough understanding how to emphasize on words in your sentence because according to me in the spoken aspect of English these are the main three points to focus on logic, etiquettes & and emphasis on significant things. These techniques can come real handy.
3. The more interesting sentences you make, the more interested listeners would be. Interesting sentences don't necessarily mean having a lot of academic words/ bookish language/ so-called classy language. As most of the people in India don't know posh English, I'd say not to take advice to be classy in English from an Indian or any non-native English speaker.
But what you can do is, use some catchy phrases or idioms just for the sake of humour or sarcasm or contractions or whatever you find you should have that in your speech. Hey, after all, it's your words which you are speaking, your mouth your rules??.

Now I know that this answer is going to give you insights about the question. But also you should not forget the fact that it's a student-teacher interaction portal and I'm a spoken English teacher.