Dear @sultan-aceh,
I should say after roaming around your blog and looking at your drawings, I've got a feeling that you have an eye for a specific female face (I don't mean repetitive, I mean you got a taste for this face form, I guess!).
Also a suggestion from someone who knows nothing about drawing and also has no idea what is he suggesting you right now;

Maybe working on shadows and giving some lighting to the face would be a good next step.

Anyway, I have no idea what I'm suggesting you! :D Nice drawing.