I need a professional book cover---simple and classy.

My book is titled "How to Master the Art of Writing a Children's Book." I need a sophisticated book cover that is friendly rather than stuffy. It needs to represent the high quality of information I am offering. Nothing childish, frilly or busy. Just simple, sophisticated and attractive. The font must be easy to read, but not childish. I am open to any color scheme. The book will be available worldwide and you will be given credit for the design. The book measures 6x9.