Amy Walker, who is an American actress, singer and accent expert, gives a fun, in-depth tutorial series on perfecting your Standard American Accent.
This tutorial comprises of 8 videos:
Standard American Accent Tutorial - Introduction
Standard American Accent Tutorial - Warm Up
Standard American Accent Tutorial - Part 1_ Vowel Sounds
Standard American Accent Tutorial - Part 2_ Consonants and Letter Combinations
Standard American Accent Tutorial - Part 3_ The Melody
Standard American Accent Tutorial - Part 4_ The Rhythm
Standard American Accent Tutorial - Part 5_ The Vibe
Standard American Accent - Bonus Video