The strong points in the original painting are:

• Very Nice! I really don't see much area for improvement. I see many pluses in this drawing:
• You simplified the bottom part of the painting and gave it a blurry look. This was well thought out. Had you defined that area, you would've pulled the viewer away from the facial part.
• The hair of the red doll was right on using a red-orange hue. This reinforces your focal point.
• There is plenty of breathing space in the painting. This is vital for portraits.
• I also agree that you suggested the plant by the window. There is no doubt what your center of interest is.

The images to the left are electronically enhanced copies, with the suggestions of the critiquers incorporated directly into the image (as shown by the areas that are highlighted).

Specific comments are below.

Areas to work on:

Only if I want to get picky. In your original drawing you had a line next to the window. It is recommendable to leave out straight lines and other geometrical figures in traditional art. Also the viewer's eye tends to get
trapped and follow lines In this case exiting through the top. If you take a look at my modification you may see that element was not necessary. I also decreased the value contrast on the window frame.

Additional comments:
Congratulations! Well done!