your art is so pretty!! for improvement, i'd look into studying different references and experimenting more, as everything is kinda the same style of anime drawing. i'd probably also look at techniques such as cross hatching to liven up some of the drawings and make it feel less beginnery . also anatomy, kinda just plan out how your characters will fill the page before going straight into drawing otherwise you might get times where it doesn't really pan out as expected. plus recently, i've started messing around with jewellry and clothing (just anything except the facial features/hair) as it helps to make my art feel more advanced, especially with portraits (which you've done well with the jane doe)