You begin with an oval (head) with the hairline on top of it. After that you continue with the lines for arms, legs and the upper part of the body.
You continue with drawing the hair. Just four balls and a hemicycle with some jags. You can work on the head shape if you want. After that you draw two parallel lines as eyes, a point as nose and the mouth. Now you can add two circles as cheeks.
This step is the most complicated step in this tutorial. You connect the arm-line with the body-line and expandet the last part of the arm a littlebit- so you have the sleeves. After that you draw the two lines on the upper part of the body and continue with the rest of I-Pin's red top. It's very simple so I think you see all what you need in the picture. ;) After making her top you continue with the legs, easy too. You can orientate yourself on the lines you draw at the beginning.
Now you add the hands and feets.
Now you can clean all the reference lines from the beginning and colour the picture if you want.