I can't give you the advice you want, but I will give your advice you need:
The books you need to read are models, not how-to guides. Count me among those who, unlike the many you mention, do not highly regard any book that markets itself 'for dummies'. More specifically, the industry of teaching people how to write creative works is a parasitic and intrinsically dishonest one.
Which books you choose as models (not for content but for technique) is important, but you must rely on the quality of your own taste.
On a side note, I would be careful of assuming that short works make for easy writing. Writing a children's book is not easy: unlike most other forms of writing, you cannot write for a reader just like yourself. Remarkable sympathetic projection is required to know what will appeal to a young reader.