[Ki-Mono]

Alrighty~! Children.. the bane of every artists existence!
Kids are weird, man. I'll try and break it down:

In order to make this drawing, I simply put it "little girl" into Google images. I used a little bit of everything I saw, so I won't credit a single picture for this drawing. I wasn't exactly sure on the age range of the child you wanted. The girl I ended up drawing looks around 6 ¯\_(ツ)_/¯
To draw kids, the main thing you have to remember is round. Everything about them is round, chubby, and soft. Try to avoid hard angles. Smooth out elbows, knees, cheeks, noses, and shoulders. The main base of the body will generally be an oval or rectangle (depending on the age of the child). Forehead plays a big part. Their forehead is usually quite large. The Younger the kid, the bigger the forehead lol. Depending on the child's age, you could also add missing teeth to further highlight the fact they are young.
To make things easier, here are some comparisons of children and adults:
On kids, the cheekbones will be lower and rounder. An adult with have higher cheekbones with a slimmer face.
A child's body can be drawn in two sections: top and bottom. An adult will have top, middle, and bottom.
Eyes will be larger and the nose will be smaller then an adults.
Adult hands are generally the size of the face, but with a child you can draw them smaller. The younger, the smaller. And of course, chubby short fingers.
On an adult, their should length is about the size of two "extra" heads. On a child, the head is bigger, and thus two heads may not fit. The younger the child, the smaller the shoulder length will be.

Curly hair is hard, because there are many different types of curly hair. I went with something natural and messy.
In my opinion, hair is evil in the sense it's easy to sketch but hard to lineart. Especially curly hair. It's gonna take trail and error on your part.
To get the look I was going for, basically just plop a cloud on the girl's head, or imagine her as a sheep. Draw a semi circle and make it lumpy by adding "hills". From there, there are no rules. Go crazy with random strands of hair and fly-aways breaking from the main shape. Try to at least persevere the forehead length, since that is a key staple for drawing a child.

When it comes to eyes, I recommend just looking up pictures of eyes and having a go at drawing them. I have a small example at the bottom there, but I found that just looking at references is the best for this kind of thing. The best part is that eyes can be drawn in many different styles of simplicity and still look good. So to add to my earlier though; be sure to look up some of your favorite cartoons and anime, and draw eyes in that style. As you can see, the eyes I put on my draw and your drawing look very different, but I feel they both look just fine. My style of drawing eyes is all over the place and changes based on my mood.
Look up different styles, try them all out, and find what works best for you.

P.S. I apologize for the shoddy redline I did over top of your drawing. I wanted to just change a few things without doing all of it, but then I started doing all of it so I tried to dial it back a bit but now it looks so awkward. Hopefully it got the point across that you can draw a young looking character without drawing it semi realism like my side ^-^;

Edit: Decided it was important to add some of the refs I used, even though it was a mash of a lot. x x x x x x x x

[•boo•]

HOLY POTATO-
THANK YOU!
I know Imma need this in the future QwQ

[Ki-Mono]

HOLY POTATO-
THANK YOU!
I know Imma need this in the future QwQ

Hey! So glad you found it helpful!!
If you want help with more, please check out my Red Lining HQ!

[woopperoni]

Oh my GOD THIS IS SO CUTE!!! Also so helpful thank you so much ((( if I ever draw a kid that I’m proud of I’ll let you know hhahahha

[Ki-Mono]

Oh my GOD THIS IS SO CUTE!!! Also so helpful thank you so much ((( if I ever draw a kid that I’m proud of I’ll let you know hhahahha

I would love to see it~~