Here is a list from the British English coach with 33 tips for speaking better English. Read the article for full details.
1. Record yourself speaking English
2. Read aloud, especially dialogue.
3. Sing along to English songs while you’re driving or in the shower.
4. Watch short video clips and pause and repeat what you hear.
5. Learn vowel and consonant sounds in English.
6. Learn and identify schwa.
7. Learn about weak and strong forms of common words.
8. Learn about word stress.
9. Learn about sentence stress.
10. Identify fixed and semi-fixed phrases and practise them.
11. Learn about collocations.
12. Replace regular verbs with phrasal verbs.
13. Learn short automatic responses.
14. Practise telling stories and using narrative tenses.
15. Learn when to pause for effect.
16. Learn about chunking.
17. Learn about typical pronunciation problems in your first language.
18. Choose an accent you like and imitate it.
19. Find an actor/actress you like and identify what makes them powerful speakers.
20. Use a mirror and / or a sheet of paper for identifying aspirated and non-aspirated sounds.
21. Practise tongue twisters.
22. Practise spelling names, numbers and dates aloud.
23. Learn about common intonation patterns.
24. Learn about places of articulation.
25. After looking at places of articulation, practise making the movements that native speakers use when they speak.
26. Learn why English is a stress-timed language.
27. Learn how to interrupt and interject politely and successfully.
28. Learn about ellipsis, assimilation and linking sounds.
29. Speak lower not higher.
30. Listen and read along to poetry (or rap songs) to practise the rhythm of English.
31. Learn exclamation words and fillers.
32. Learn how to paraphrase.
33. Use contractions more.
Now read the article for full details.