The sound /r/ is quite different to the Spanish /r/. The English /r/ is not articulated with the tip of the tongue touching the roof of the mouth. Rather the front of the tongue (not the tip!) curls upwards and rises towards the top of the mouth cavity.
Another big difference between Spanish /r/ and /English /r/ is the in initial position (at the beginning of a word), Spanish /r/ is pronounced like a double ‘r’. Try saying the words rojo and perro. In both words the /r/ is the same. In English initial rs are much softer and do not vibrate in the same way.
PRONOUNCING ‘R’ AT THE END OF SYLLABLES
Another important thing to say about /r/ is that in the English language, pronouncing or not the ‘r’ that comes at the end of a syllable divides the different varieties of the English spoken in the world into two main groups (according to this criteria), rhotic and non-rhotic.
Rhotic or non-rhotic refers to the sounding of ‘r’ at the end of syllables e,g, car /ka:/ or /ka:r/.
The variety of English spoken in England does not sound the post syllabic ‘r’ whereas General American, Irish English and Scottish English, do pronounce the ‘rs’ at the end of syllables.
Some non-rhotic English varieties are: British English and New Zealand English.
The spelling of this sound is usually r or rr like in: red and carry /red/ /kæri/