Here you see a adult male. He has a big cloa, with below it some larger scales. Also by the pores on the hind legs, you can recognize him. When they're young the pores are not as pronounced, and are harder to see.
The body of a male is heavier/broader than a female. Especially the jaws are broader. With juveniles animals, you can already see the hemipenis. The tail is thicker on both sides behind their cloa.
Young males are more difficult to recognize. It can better be easier to sex a young female. Automatically you get the little males left.
If you look at this adult female you can see that the cloa is much smoother. Also the scales under the cloa are smaller.
The best way to recognize females, are the dark dots that you can find on both sides under the cloa. You can see them verry well on the photo. Believe me..... With this, you make the best chance to recognize their sexes. Certain when the animals are verry small.