https://www.youtube.com/user/EmRatThichVo/

for beginners
https://www.youtube.com/playlist?list=PLnSKFBegbrmul_KlDH1N2-tBg0Oq5t5XX
https://www.youtube.com/playlist?list=PLnSKFBegbrmsgCAkXgUGz9OBRmIrtjIQ_
tips and technics
https://www.youtube.com/playlist?list=PLnSKFBegbrmsovf4HDVrGYn1AUPNy-J7I