A comprehensive series of 87 tutorials:
https://www.youtube.com/watch?v=Hl-zzrqQoSE&list=PLFE2CE09D83EE3E28
Another series of 48 tutorials:
https://www.youtube.com/watch?v=fEApt1B8ycs&list=PL691F825EFC74A181
Another series of 25 tutorials (indian accent):
https://www.youtube.com/watch?v=DyHNp6oE7RI&list=PL54846BE87A95E78A