I currently live in Sweden and I'm planning to travel to UK for my further studies in about four years. My biggest problem is English. I am the best in my class in English, but I can't really talk like a native American or Englishman. Can you recommend me some literature or other tips so I could develop my English writing and speaking skills?
It would really help!

Read American Newspapers. The Atlanta Journal Constitution online edition is free. Understand that American newspapers are written at a fifth-grade level, but they are edited for most grammitical errors. Other easy-to-read options would be John Grisham novels.

I agree with the previous post. I would add that there are a lot of other writings out there there would be available in both languages. Therefore, you can find an essay in your native language and English. It will give you a point of reference of how things translate to English.

Have you had a chance to try this technique yet? When you do get a chance, please share your feedback! I always like to know if this technique is found beneficial! Thanks.
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Essay

A good way to improve your writing skills is to use microsoft word. Change your language to English on microsoft word and practise writing. See what mistakes are highlighted. This is good for spelling and grammar. But to really improve you can have someone check it for you as word is limited. This could be one of your friends or a tutor.

In terms of your English speaking skills a one to one English course is a great way to improve. If you can't find a tutor in your area then look for one online, taking the course through skype.

Just to add there are many ways that you could improve through self study. There are many ways to study English online with English grammar resources. For example, if you would like to improve using the present perfect simple you could find websites that offer that.

If you would like to speak English more you could find a language exchange. There are many websites that offer this and this is great for your English conversation.