There are just some sounds que no me salen

I totally sympathize with my students. Just like they have problems pronouncing God, and other word that I can't think of at the moment, I have the hardest time pronouncing:

--madre/padre

--luego

--agua

--drama

--aire

--any word with double Rs

--any word with a final r.

Thus I have a long list of things that I need to improve. Poco a poco, no.


Switching topics, I spent the afternoon trying to find exercises to teach the kids English vowels. Since English has 11 vowel sounds and Spanish has only 5, it's natural that they find some sounds both difficult to distinguish and produce. Any ideas about how to go about teaching them?