Practice a few minutes each day with someone on Skype . Record the conversations and listen to it whenever possible. Immersion is best, so maybe a student exchange program would be ideal. I know is expensive and time consuming, so try Skype for now.

I would recommend maybe watching a lot of television shows or movies. Hearing it clearly on TV may help. If you have nice friends maybe they could practice with you. Even if you have online language partners maybe you could find a way to practice that way.

Immersion is key, albeit you'd want to be careful if you're going to watch films in English because they could have slang or different variants of English. I'd suggest learning the European variant of English as its similar to most other variants of English , whereas American English is not as similar to other variants of English

Speak with natives. If you need to hear how a word is pronounced, let me know and I will record it for you. :)

find a couple language exchange partners on skype and practice 15 minutes a day with them. consistent practice is the only way...