Read and listen to Norwegian as often as possible. Change the language of all your devices and apps to Norwegian. Find a native Norwegian to practice with on www.verbling.com (I don't know how many native Norwegians you can find there, but it's worth the try). Watch movies in Norwegian if possible. Watch Norwegian television programs: http://tv.nrk.no/programmer/utland

If you have any Norwegian-related questions or if you want me to correct your Norwegian (I am a native Norwegian), I'd be happy to help you in the forums on my own website as well: http://www.learnnorwegiannaturally.com/forums/

Good luck!