Do not worry, that happens to everyone!
If you find it difficult to use UK English, this page may help you out:
BBC Learning English | Home page
If you find it difficult to pronounce the sounds of UK English, maybe this webpage may help out: start downloading the videos, each symbol has a video
BBC Learning English | Pronunciation Tips
As a learner, you should not stop listening to real English: Here are a lot of podcast you may start downloading (subscribe to those one you find more interesting, there are many subjects, use the feed readers)
BBC - Radio - Podcasts - Directory
How to use English in a general way:
If you like listening to radio:
As for the book: I recommend "Practical English Usage", by Michael Swan. OXFORD.
For more details, PM me. I have a lot of interesting information I'd like to share.
Student or Learner