The r sound is a distinctive one in the English
language and has the most variation among the native speakers of English. In all English dialects the r is pronounced at the beginning of a word or the start of a new syllable. In the UK, Australia, South Africa and others the r is usually silent at the end of the word unless the next word begins with a vowel. In America, Canada, and some parts of the UK the r is almost always pronounced (these are called rhotic accents). The goal of this article is to give you a firrrmerrr grasp of the American r so you can speak more clearly and with confidence.
Speakers of other languages often think of American English sounds as if the speaker has a wad of gum in their mouth. It is true, English, and especially American English uses the jaw to form words more than other languages. Do not be afraid to open your mouth wide to allow the full vowels to come out. Notice how the speakers open their mouth when speaking and try to emulate it when speaking yourself.
The r is a gnarling sound where the sound is focused at the front of the mouth. The tongue must point to just behind the ridge that lies just behind your teeth when producing the r sound, however do not allow the tongue to touch the ridge. It must gently point upward. Try modulating from the open ah sound to the arrr sound by gently closing your jaw and raising your tongue to produce the sound until it becomes easy and second nature. This sound is pronounced even at the end of sentences. Do not over do it, remember, the r is natural and shouldn't cause any strain in your jaw.
Watching American media is a great way to get a grasp on the sounds, as well as getting as much conversation practice as possible with native speakers.