1) Pay close attention to how American English speakers form their words when you interact communicate with them. Watch the motions of their mouth and lips and practice the idiomatic expressions they use when they speak.
2) Each language has a distinct rhythm and English is no exception. Find a language CD and listen to it over and over while you are driving in your car or have free time. This will get used to the rhythm of American English speakers.
3) When you are speaking, be sure to take your time and breathe slowly. Many other languages are spoken at a much faster tempo than English and you want to be sure you are speaking in a calm and coherent manner so you are understood. Once you gain the confidence you can always speed up your tempo from that point.
4) Practice is a very important. Try to read English out loud every day for at least 30 minutes if you have the time. This will help get you used to pronouncing common expressions and phrases. If you have a recording device, try recording yourself and listen back to focus on the improvements you can make.
5) Perhaps the most important technique to improving your accent is to surround yourself around native English speakers and continuously receive feedback from them on how your accent training is improving. They should be able to help you focus on areas where you are having trouble and help you improve. There should be clubs and social organizations in your local area where you can meet people.
Belinda