I cannot offer more constructive advise than the way it has been offered. I do have the talent to make a canvas sing with beauty the way you can, but I do know what I like and what is not quit correct. Her hair as rendered is blonde. I do not know how to be more constructive than that since I cannot paint myself. What I see is a character that is blonde in a suit similar to the Sheila character. If she was a real person would you have painted her that way? There are dozens of Sheila renditions in dozens of styles here and in other sites and the things that make her Sheila are red hair, freckles, purple suit and cloak with high boots. What is interesting about your work is the pose and background. Most other works simple plop her and / or the gang in the middle of some kind of background with some kind of monsters.
Her look to the left at something we cannot see is very intriguing and made me stop to look again. It is that unknown quality just out of site that drew me in, is very well done. At the time there was no need to restate that fact as it has been said in several of the other notes on this piece, so I did not.
I could not help but notice that you have taken the time to write a rather long and defensive response to my very simple critique. I am hoping that means you would enjoy an exchange of ideas which I would welcome. In that vein I will continue. Her head is too round. It may be from the cut of the hair as depicted. However no human form is that perfectly symmetrical. I thought of a pumpkin when I looked at it twice. Again, not being an artist I do not know what to tell you for a fix. I did look at my daughters hair for some time and had her flip her hair in a twisting motion to the left, none of her efforts looked that round. Perhaps finding a model to work with to get the proportions different would help.
Then there is the size of the legs. They are very large in circumference in ratio to her body and the space between them looks like she has four foot wide hips. Again perhaps a model would help.
Other than that I cannot say how to fix an artistic problem, just that I know what looks correct and what does not. Perhaps there are other artiest that can supply advise. If you do not know there is a perceived problem it cannot be improved can it?
However when it comes to e-mail, blogs and so on there are certain courtesies. Yes, a question mark after a statement then a following statement telling the viewer they can go . . . do it themselves is patronizing. Yes, any time capital letters are used for an entire word or more or for the first letter in every word in a sentence, it is considered YELLING.
Every artist is different as are all humans. How can I tell you what really helps other than personal tastes? How do you grow if all your work is perfect right out of the block? Let your audience spark your curiosity and let curiosity spark your genius. Never listen to your ego.
For me I write stories. I have been in writers groups plus toast masters and love the feedback from every club no matter what form it comes in. My favorite lines are 'how can I help' and 'how interesting, please explain/continue/tell me more/help me understand'. For this old fart it is a good way to learn . . . even at 50+.
If at first you do not succeed, try, try again . . .
. . . unless you are skydiving, then you better get it right every time.