I started painting with acrylics like a week ago and have no previous experience with any trad media so I don't really know what am I doing. How do I blend the colors? How do I mix them? Do I do the sketch first and partially paint some features or do I paint completely over it and then make another sketch and paint on top of it too?

Please, do you know any artist that may have an useful tutorial or a book?

Thank you.