Many people, not be the letter "R", don't worry about it. But there are those who seek perfection in everything, including his own speech. If you are one of them, consult a good speech therapist is a specialist working with speech disorders. It will help you in the short term to correct deficiencies in pronunciation, of course, with proper diligence in your part.
If you have not enough free time to visit a speech therapist or prefer independent study, you may help yourself by performing a simple set of exercises. These exercises develop the vocal apparatus, the muscles of the lips and tongue, produce the desired pronunciation. You can find them in the textbooks on the therapy and on the Internet.
Here are the main exercises for correction of the letter "R". Alternately smile and stretch your lips into a tube, it can say "and". Repeat it several times. Open your mouth, immerse the tip of the tongue to the lower heaven, then raise to the top (this exercise is called "Swing"). Do such movements of the tongue from side to side as if you were brushing your teeth. Open your mouth, lift the tip of the tongue to the upper palate and hold for a few seconds ("Blade"). "Fungus": let your tongue seemed to stick to the upper palate. Click the tongue on the upper palate (the exercise "Horse"). Hug your upper lip with the tongue, as if licking delicious jam. Imagine what blow off cotton wool from a nose.
To model the vibration and "growl". Open your mouth and knock the tip of his tongue over the bumps near the upper teeth, while you say "d-d-d...". Gradually translate to "Dr-R-R-R...". Imagine that, crank the engine: "Tr-R-R-R...". In this case, the consonants "t" or "d" before "R" are complementary, because often it is difficult to immediately start to "growl". As a workout, you can do without it.
When growl "Dr" and "Tr" is produced you well enough, but the letter "p" has not yet vents, begin to read sentences and poems, where there is a combination of the sounds "Tr" or "Dr", for example: sailors, tram, friends, yeast. Then go to the verses where there is the letter "R" in combination with various other. You can read and prose. Remember to do this every day, because the most important thing here is perseverance and desire. Mental attitude is very important. Remember, as someone pronounces the letter "R" and imagine that you pronounce it well. Then you reflexively will try to repeat the same movements of the vocal apparatus, and it is much more effective than just mechanically doing the exercises.
Practice the tongue twisters with the letter "R", for example: "On the courtyard grass, on a grass firewood," "the Three ravens at the gate, three magpies on the threshold," etc.
Record yourself from the side to evaluate your speech much easier.