English is a confusing language when it comes to speaking. There are a lot of methods to become a better speaker in any language:
1. TV Shows/Movies/Music - This is a listening skill, but listening to pronunciation and how voices rise and fall in a sentence is really important to learn how to sound like a native speaker.
2. Talk to yourself in the language you are learning - I always talk to myself in Korean and Japanese because it helps me remember how to sound fluent.
3. Listen to your own voice - I recommend recording a voice message and listening to it. This will help you realise your mistakes in speaking and pronunciation.
4. Start small - start with some simple expressions like "Oh my god!" "Hey what's going on" "I'm so late" "How on earth is that possible?"
5. Choose one accent - Some people when they learn english have really weird accents because they change all the time. My advice is choose one. There are many: British, American, Australian, Canadian, New Zealand, Singaporean, South African etc.
I hope this helps!