Listen a lot to English video- and audio materials and try to practice with a native speaker on Skype like the ones before me were suggesting. This newswebsite is also very good: http://www.radio.cz/en. The newswebsite is in six different languages (including English) and the written articles also have a spoken version in audio format. In this way, you can match what you hear with what you see! Check this article as an example: http://www.radio.cz/en/section/curraffrs/prague-endorses-turkeys-eu-candidacy

I definitely wouldn´t recommend google translate for improving pronunciation, it's just not natural and it's absolutely boring... What I did the most is listening to the podcast on my mp3. Those are short episodes with real-life situations and are suitable for all levels, as you can find a lot of it online. The one I liked the most is the one from British Council learning portal. They talk about loads of interesting everyday topics, jokes, so there is something for everyone :) here is the link: http://learnenglish.britishcouncil.org/en/elementary-podcasts In the podcast there is also a girl who came to UK from Venezuela, if I remember well, and all the funny situations she went trough while learning english. Although it's called elementary podcast, it can help a lot to someone on higher level as well... I hope it will help you, and have a good time listening to it :)

I offer lessons using the book "Clear Speech". The book comes with a cd for the student. You will learn pronunciation by learning about syllables. I work for ETS (Educational Testing Service). They administer the test called TOEFL and TOEIC. I am a certified examiner for the TOEIC test. One component of this test involves me listening to students reading paragraphs and I score their intonation as well as pronunciation. Because of this I believe I have an advantage in helping you. But, if you want to study on your own I would suggest using the book "Clear Speech". As an Asian I know that your difficulties are with the letter "p", "v", "r" and "l" sounds.

You tube or Skype with a native speaker

Best way i can think of is to watch english movies you like and just repeat what they say.