Yes, I agree with everyJuan...

The videos linked to the one Villa posted are very good too... (I am just listening to one as I post... and I think from an Amerrican orr even forreign viewpoint these are helpful...)

(Just rrremembered once, when I had to do some parrrody of a Gerrrman or Rrrrusian scientists... I had some fun exagerrrrating the "rrrsss" to the utmost...) (That could be another aproach, if you are not shy and want to play with the sounds...) (My two additional rrrupiahs...)

I also remembered the one that goes,
El perro de San Roque no tiene rabo,
porque Ramón Ramírez
se lo ha cortado...

And you can drrrill, drrrill, drill... (hasta que las rrranas crrríen pelo...)

Here is one I practiced a lot and it helped me mucho to roll my "Rs".

Roberto y Enrique paseaban alrededor de la reja. Querían entregar el recado,
pero la cosa estaba tan enredada que optaron por esperar un hora más.
No estaban enterados de que estaba enterrado el rico que había residido
en ese barrio de Roma.

Robert and Henry went around the gate. They wanted to deliver the message
but the thing was so mixed up that they decided to wait for an hour more.
They were not aware that the rich man that was buried had lived in that
neighborhood of Rome.

Too right!
(like the Australians say) (Used as an expression of emphatic agreement.)