I got this free tutorial from the link below.
http://easymakesmehappy.blogspot.com/2010/04/rainbow-necklace-skill-level-easy-peasy.html
http://easymakesmehappy.blogspot.com/2010/04/rainbow-necklace-skill-level-easy-peasy.html
Crochet and stitching are my hobbies so it's all here. I included some interesting trivia because I believe it's another way of educating myself with history and facts.
Mine accidentaly came out oval shaped instead of round. I only needed to try how to crochet a ball so I followed the instructions from the link mentioned below sadly my ball did not turn out round, it's oval ( very funny ). Well nothing's harm on trying, I guess I haven't followed the instructions well. My crochet ball looks like more of a hanging cocoon. lol! I think I skipped some stitches while finishing, it's decreased so it turned long.
I have a black metallic/iron headband (1 cm thin). It's color has faded so I decided to improvise it for my daughter. 

I did 2 solid granny squares (5 rounds each) on this one following the pattern of Teresa Richardson. I just used a dark red yarn instead of a pink one. Then for the side part I did 2 rows of double crochet with a length of 30 cms. using a pink yarn for a contrast color. I used black yarn to attach the pink side and the solid granny square together.