A illustration finished some time ago, but I like it and want to fix mistakes. If may happen, so when try to improve all, something may go out-of-order, because I used to act first and think later.
May I ask for your help?
One thing that really bugs me about this piece is that you've tried to do some kind of distance blur with the airships, but not on the distant city.
You would also do well to separate your values more. The whole thing is just too much in the same range from top to bottom and side to side. Try placing lighter shapes against darker ones and vice versa to create a more readable composition.
Also, your title mentions that this is an idea for a cover of some sort. I am not sure you have given any thought to where the text is going to go.
As the ego shrinks, so the spirit expands.
There is too much going on this picture for my liking, and what about the shape of dragon,are those its wings near the women holding the flower?What is going with its body?
It feels like your cramming all these characters in,evidently showing no real planning took place.
A smooth sea never made a skillful sailor.
Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so."
I could concede that this style of having no value separation could be viable, and maybe even appealing because lots of people like that comic book line art. However, there are still a lot of issues with anatomy and composition which was mentioned. Your art will always look amateur until you address those issues.
I highly recommend not wasting your time trying to fix old work. Take what you've learned(you said you know your weakness of poor planning), so improve now, and make a better painting.