Sketchbook

I takes a summer class which is about location drawing and painting. We went to different spots to draw and paint every weeks. I have lot of fun. And it's an relaxed class, except the thing that we need to finish 100 pages is a large pressure... I try me best.
Here're some sketches I did and liked so far.

Book cover for Smiling Mail

Ummm...why I feel I failed in doing this book cover.

The value study is fine, but I'm not good at choosing color...

Somehow, I feel this book cover is not attractive...

Hope someone can give me some suggestion, please. 

Watercolor and brown ink, 10"x16".

Smiling Mail, own children's book, work in progress

I'm working on my own children's book, which is my final project from Spring semester.
I try to finish it step by step. Hope I can finish all in 6 months.
This page is the last page of the story.
Watercolor + brown ink + a little of gouache. 8"x10".