Memorize, memorize, memorize. You have to memorize the phrases and then don't be afraid to use them whenever you meet a speaker of Arabic. Children learn fast because they love testing using new words they just picked up and they keep using it and with trial and error understand in which context they can use it and the right pronunciation. Also, try to learn the language without translation. You may translate sometimes as a learning strategy but don't transliterate everything and translate everything to the point that you're doing everything in your native language instead of Arabic. :) I hope you find this helpful.